LinuxLists.cc - [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF

2024-01-29 01:24:45

Subject: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

=== Description ===

This is a bpf-treewide change that annotates all kfuncs as such inside
BTF_ids. This annotation eventually allows us to automatically generate
kfunc prototypes from bpftool.

We store this metadata inside a yet-unused flags field inside struct
btf_id_set8 (thanks Kumar!). pahole will be taught where to look.

More details about the full chain of events are available in commit 3's
description.

The accompanying pahole and bpftool changes can be viewed
here on these "frozen" branches [0][1].

[0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
[1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed

=== Changelog ===

Changes from v3:
* Rebase to bpf-next and add missing annotation on new kfunc

Changes from v2:
* Only WARN() for vmlinux kfuncs

Changes from v1:
* Move WARN_ON() up a call level
* Also return error when kfunc set is not properly tagged
* Use BTF_KFUNCS_START/END instead of flags
* Rename BTF_SET8_KFUNC to BTF_SET8_KFUNCS

Daniel Xu (3):
bpf: btf: Support flags for BTF_SET8 sets
bpf: btf: Add BTF_KFUNCS_START/END macro pair
bpf: treewide: Annotate BPF kfuncs in BTF

Documentation/bpf/kfuncs.rst | 8 +++----
drivers/hid/bpf/hid_bpf_dispatch.c | 8 +++----
fs/verity/measure.c | 4 ++--
include/linux/btf_ids.h | 21 +++++++++++++++----
kernel/bpf/btf.c | 8 +++++++
kernel/bpf/cpumask.c | 4 ++--
kernel/bpf/helpers.c | 8 +++----
kernel/bpf/map_iter.c | 4 ++--
kernel/cgroup/rstat.c | 4 ++--
kernel/trace/bpf_trace.c | 8 +++----
net/bpf/test_run.c | 8 +++----
net/core/filter.c | 20 +++++++++---------
net/core/xdp.c | 4 ++--
net/ipv4/bpf_tcp_ca.c | 4 ++--
net/ipv4/fou_bpf.c | 4 ++--
net/ipv4/tcp_bbr.c | 4 ++--
net/ipv4/tcp_cubic.c | 4 ++--
net/ipv4/tcp_dctcp.c | 4 ++--
net/netfilter/nf_conntrack_bpf.c | 4 ++--
net/netfilter/nf_nat_bpf.c | 4 ++--
net/xfrm/xfrm_interface_bpf.c | 4 ++--
net/xfrm/xfrm_state_bpf.c | 4 ++--
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 8 +++----
23 files changed, 87 insertions(+), 66 deletions(-)

--
2.42.1

2024-01-29 01:25:17

by Daniel Xu

[permalink] [raw]

Subject: [PATCH bpf-next v4 2/3] bpf: btf: Add BTF_KFUNCS_START/END macro pair

This macro pair is functionally equivalent to BTF_SET8_START/END, except
with BTF_SET8_KFUNCS flag set in the btf_id_set8 flags field. The next
commit will codemod all kfunc set8s to this new variant such that all
kfuncs are tagged as such in .BTF_ids section.

Signed-off-by: Daniel Xu <[email protected]>
---
include/linux/btf_ids.h | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index dca09b7f21dc..0fe4f1cd1918 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -8,6 +8,9 @@ struct btf_id_set {
u32 ids[];
};

+/* This flag implies BTF_SET8 holds kfunc(s) */
+#define BTF_SET8_KFUNCS (1 << 0)
+
struct btf_id_set8 {
u32 cnt;
u32 flags;
@@ -204,6 +207,12 @@ asm( \
".popsection; \n"); \
extern struct btf_id_set8 name;

+#define BTF_KFUNCS_START(name) \
+__BTF_SET8_START(name, local, BTF_SET8_KFUNCS)
+
+#define BTF_KFUNCS_END(name) \
+BTF_SET8_END(name)
+
#else

#define BTF_ID_LIST(name) static u32 __maybe_unused name[64];
@@ -218,6 +227,8 @@ extern struct btf_id_set8 name;
#define BTF_SET_END(name)
#define BTF_SET8_START(name) static struct btf_id_set8 __maybe_unused name = { 0 };
#define BTF_SET8_END(name)
+#define BTF_KFUNCS_START(name) static struct btf_id_set8 __maybe_unused name = { 0 };
+#define BTF_KFUNCS_END(name)

#endif /* CONFIG_DEBUG_INFO_BTF */

--
2.42.1

2024-01-29 01:25:39

by Daniel Xu

[permalink] [raw]

Subject: [PATCH bpf-next v4 1/3] bpf: btf: Support flags for BTF_SET8 sets

This commit adds support for flags on BTF_SET8s. struct btf_id_set8
already supported 32 bits worth of flags, but was only used for
alignment purposes before.

We now use these bits to encode flags. The first use case is tagging
kfunc sets with a flag so that pahole can recognize which
BTF_ID_FLAGS(func, ..) are actual kfuncs.

Signed-off-by: Daniel Xu <[email protected]>
---
include/linux/btf_ids.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index a9cb10b0e2e9..dca09b7f21dc 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -21,6 +21,7 @@ struct btf_id_set8 {

#include <linux/compiler.h> /* for __PASTE */
#include <linux/compiler_attributes.h> /* for __maybe_unused */
+#include <linux/stringify.h>

/*
* Following macros help to define lists of BTF IDs placed
@@ -183,17 +184,18 @@ extern struct btf_id_set name;
* .word (1 << 3) | (1 << 1) | (1 << 2)
*
*/
-#define __BTF_SET8_START(name, scope) \
+#define __BTF_SET8_START(name, scope, flags) \
+__BTF_ID_LIST(name, local) \
asm( \
".pushsection " BTF_IDS_SECTION ",\"a\"; \n" \
"." #scope " __BTF_ID__set8__" #name "; \n" \
"__BTF_ID__set8__" #name ":; \n" \
-".zero 8 \n" \
+".zero 4 \n" \
+".long " __stringify(flags) "\n" \
".popsection; \n");

#define BTF_SET8_START(name) \
-__BTF_ID_LIST(name, local) \
-__BTF_SET8_START(name, local)
+__BTF_SET8_START(name, local, 0)

#define BTF_SET8_END(name) \
asm( \
--
2.42.1

2024-01-29 01:25:46

by Daniel Xu

[permalink] [raw]

Subject: [PATCH bpf-next v4 3/3] bpf: treewide: Annotate BPF kfuncs in BTF

This commit marks kfuncs as such inside the .BTF_ids section. The upshot
of these annotations is that we'll be able to automatically generate
kfunc prototypes for downstream users. The process is as follows:

1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs
2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for
each function inside BTF_KFUNCS sets
3. At runtime, vmlinux or module BTF is made available in sysfs
4. At runtime, bpftool (or similar) can look at provided BTF and
generate appropriate prototypes for functions with "bpf_kfunc" tag

To ensure future kfunc are similarly tagged, we now also return error
inside kfunc registration for untagged kfuncs. For vmlinux kfuncs,
we also WARN(), as initcall machinery does not handle errors.

Signed-off-by: Daniel Xu <[email protected]>
---
Documentation/bpf/kfuncs.rst | 8 ++++----
drivers/hid/bpf/hid_bpf_dispatch.c | 8 ++++----
fs/verity/measure.c | 4 ++--
kernel/bpf/btf.c | 8 ++++++++
kernel/bpf/cpumask.c | 4 ++--
kernel/bpf/helpers.c | 8 ++++----
kernel/bpf/map_iter.c | 4 ++--
kernel/cgroup/rstat.c | 4 ++--
kernel/trace/bpf_trace.c | 8 ++++----
net/bpf/test_run.c | 8 ++++----
net/core/filter.c | 20 +++++++++----------
net/core/xdp.c | 4 ++--
net/ipv4/bpf_tcp_ca.c | 4 ++--
net/ipv4/fou_bpf.c | 4 ++--
net/ipv4/tcp_bbr.c | 4 ++--
net/ipv4/tcp_cubic.c | 4 ++--
net/ipv4/tcp_dctcp.c | 4 ++--
net/netfilter/nf_conntrack_bpf.c | 4 ++--
net/netfilter/nf_nat_bpf.c | 4 ++--
net/xfrm/xfrm_interface_bpf.c | 4 ++--
net/xfrm/xfrm_state_bpf.c | 4 ++--
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 8 ++++----
22 files changed, 70 insertions(+), 62 deletions(-)

diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst
index 7985c6615f3c..a8f5782bd833 100644
--- a/Documentation/bpf/kfuncs.rst
+++ b/Documentation/bpf/kfuncs.rst
@@ -177,10 +177,10 @@ In addition to kfuncs' arguments, verifier may need more information about the
type of kfunc(s) being registered with the BPF subsystem. To do so, we define
flags on a set of kfuncs as follows::

- BTF_SET8_START(bpf_task_set)
+ BTF_KFUNCS_START(bpf_task_set)
BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_put_pid, KF_RELEASE)
- BTF_SET8_END(bpf_task_set)
+ BTF_KFUNCS_END(bpf_task_set)

This set encodes the BTF ID of each kfunc listed above, and encodes the flags
along with it. Ofcourse, it is also allowed to specify no flags.
@@ -347,10 +347,10 @@ Once the kfunc is prepared for use, the final step to making it visible is
registering it with the BPF subsystem. Registration is done per BPF program
type. An example is shown below::

- BTF_SET8_START(bpf_task_set)
+ BTF_KFUNCS_START(bpf_task_set)
BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_put_pid, KF_RELEASE)
- BTF_SET8_END(bpf_task_set)
+ BTF_KFUNCS_END(bpf_task_set)

static const struct btf_kfunc_id_set bpf_task_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c
index d9ef45fcaeab..02c441aaa217 100644
--- a/drivers/hid/bpf/hid_bpf_dispatch.c
+++ b/drivers/hid/bpf/hid_bpf_dispatch.c
@@ -172,9 +172,9 @@ hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t rdwr
* The following set contains all functions we agree BPF programs
* can use.
*/
-BTF_SET8_START(hid_bpf_kfunc_ids)
+BTF_KFUNCS_START(hid_bpf_kfunc_ids)
BTF_ID_FLAGS(func, hid_bpf_get_data, KF_RET_NULL)
-BTF_SET8_END(hid_bpf_kfunc_ids)
+BTF_KFUNCS_END(hid_bpf_kfunc_ids)

static const struct btf_kfunc_id_set hid_bpf_kfunc_set = {
.owner = THIS_MODULE,
@@ -440,12 +440,12 @@ static const struct btf_kfunc_id_set hid_bpf_fmodret_set = {
};

/* for syscall HID-BPF */
-BTF_SET8_START(hid_bpf_syscall_kfunc_ids)
+BTF_KFUNCS_START(hid_bpf_syscall_kfunc_ids)
BTF_ID_FLAGS(func, hid_bpf_attach_prog)
BTF_ID_FLAGS(func, hid_bpf_allocate_context, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, hid_bpf_release_context, KF_RELEASE)
BTF_ID_FLAGS(func, hid_bpf_hw_request)
-BTF_SET8_END(hid_bpf_syscall_kfunc_ids)
+BTF_KFUNCS_END(hid_bpf_syscall_kfunc_ids)

static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/fs/verity/measure.c b/fs/verity/measure.c
index bf7a5f4cccaf..3969d54158d1 100644
--- a/fs/verity/measure.c
+++ b/fs/verity/measure.c
@@ -159,9 +159,9 @@ __bpf_kfunc int bpf_get_fsverity_digest(struct file *file, struct bpf_dynptr_ker

__bpf_kfunc_end_defs();

-BTF_SET8_START(fsverity_set_ids)
+BTF_KFUNCS_START(fsverity_set_ids)
BTF_ID_FLAGS(func, bpf_get_fsverity_digest, KF_TRUSTED_ARGS)
-BTF_SET8_END(fsverity_set_ids)
+BTF_KFUNCS_END(fsverity_set_ids)

static int bpf_get_fsverity_digest_filter(const struct bpf_prog *prog, u32 kfunc_id)
{
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index edef96ceffa3..bc446f37530c 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -8041,6 +8041,14 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
{
enum btf_kfunc_hook hook;

+ /* All kfuncs need to be tagged as such in BTF.
+ * WARN() for initcall registrations that do not check errors.
+ */
+ if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
+ WARN_ON(!kset->owner);
+ return -EINVAL;
+ }
+
hook = bpf_prog_type_to_kfunc_hook(prog_type);
return __register_btf_kfunc_id_set(hook, kset);
}
diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
index 2e73533a3811..dad0fb1c8e87 100644
--- a/kernel/bpf/cpumask.c
+++ b/kernel/bpf/cpumask.c
@@ -424,7 +424,7 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask)

__bpf_kfunc_end_defs();

-BTF_SET8_START(cpumask_kfunc_btf_ids)
+BTF_KFUNCS_START(cpumask_kfunc_btf_ids)
BTF_ID_FLAGS(func, bpf_cpumask_create, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_cpumask_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
@@ -450,7 +450,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_RCU)
BTF_ID_FLAGS(func, bpf_cpumask_any_distribute, KF_RCU)
BTF_ID_FLAGS(func, bpf_cpumask_any_and_distribute, KF_RCU)
BTF_ID_FLAGS(func, bpf_cpumask_weight, KF_RCU)
-BTF_SET8_END(cpumask_kfunc_btf_ids)
+BTF_KFUNCS_END(cpumask_kfunc_btf_ids)

static const struct btf_kfunc_id_set cpumask_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index bcb951a2ecf4..4db1c658254c 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2544,7 +2544,7 @@ __bpf_kfunc void bpf_throw(u64 cookie)

__bpf_kfunc_end_defs();

-BTF_SET8_START(generic_btf_ids)
+BTF_KFUNCS_START(generic_btf_ids)
#ifdef CONFIG_KEXEC_CORE
BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
#endif
@@ -2573,7 +2573,7 @@ BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
#endif
BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_throw)
-BTF_SET8_END(generic_btf_ids)
+BTF_KFUNCS_END(generic_btf_ids)

static const struct btf_kfunc_id_set generic_kfunc_set = {
.owner = THIS_MODULE,
@@ -2589,7 +2589,7 @@ BTF_ID(struct, cgroup)
BTF_ID(func, bpf_cgroup_release_dtor)
#endif

-BTF_SET8_START(common_btf_ids)
+BTF_KFUNCS_START(common_btf_ids)
BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx)
BTF_ID_FLAGS(func, bpf_rdonly_cast)
BTF_ID_FLAGS(func, bpf_rcu_read_lock)
@@ -2618,7 +2618,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null)
BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)
BTF_ID_FLAGS(func, bpf_dynptr_size)
BTF_ID_FLAGS(func, bpf_dynptr_clone)
-BTF_SET8_END(common_btf_ids)
+BTF_KFUNCS_END(common_btf_ids)

static const struct btf_kfunc_id_set common_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
index 6abd7c5df4b3..9575314f40a6 100644
--- a/kernel/bpf/map_iter.c
+++ b/kernel/bpf/map_iter.c
@@ -213,9 +213,9 @@ __bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map)

__bpf_kfunc_end_defs();

-BTF_SET8_START(bpf_map_iter_kfunc_ids)
+BTF_KFUNCS_START(bpf_map_iter_kfunc_ids)
BTF_ID_FLAGS(func, bpf_map_sum_elem_count, KF_TRUSTED_ARGS)
-BTF_SET8_END(bpf_map_iter_kfunc_ids)
+BTF_KFUNCS_END(bpf_map_iter_kfunc_ids)

static const struct btf_kfunc_id_set bpf_map_iter_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index a8350d2d63e6..07e2284bb499 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -562,10 +562,10 @@ void cgroup_base_stat_cputime_show(struct seq_file *seq)
}

/* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */
-BTF_SET8_START(bpf_rstat_kfunc_ids)
+BTF_KFUNCS_START(bpf_rstat_kfunc_ids)
BTF_ID_FLAGS(func, cgroup_rstat_updated)
BTF_ID_FLAGS(func, cgroup_rstat_flush, KF_SLEEPABLE)
-BTF_SET8_END(bpf_rstat_kfunc_ids)
+BTF_KFUNCS_END(bpf_rstat_kfunc_ids)

static const struct btf_kfunc_id_set bpf_rstat_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 64fdaf79d113..241ddf5e3895 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1412,14 +1412,14 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr,

__bpf_kfunc_end_defs();

-BTF_SET8_START(key_sig_kfunc_set)
+BTF_KFUNCS_START(key_sig_kfunc_set)
BTF_ID_FLAGS(func, bpf_lookup_user_key, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE)
BTF_ID_FLAGS(func, bpf_lookup_system_key, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE)
#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE)
#endif
-BTF_SET8_END(key_sig_kfunc_set)
+BTF_KFUNCS_END(key_sig_kfunc_set)

static const struct btf_kfunc_id_set bpf_key_sig_kfunc_set = {
.owner = THIS_MODULE,
@@ -1475,9 +1475,9 @@ __bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str,

__bpf_kfunc_end_defs();

-BTF_SET8_START(fs_kfunc_set_ids)
+BTF_KFUNCS_START(fs_kfunc_set_ids)
BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS)
-BTF_SET8_END(fs_kfunc_set_ids)
+BTF_KFUNCS_END(fs_kfunc_set_ids)

static int bpf_get_file_xattr_filter(const struct bpf_prog *prog, u32 kfunc_id)
{
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index dfd919374017..5535f9adc658 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -617,21 +617,21 @@ CFI_NOSEAL(bpf_kfunc_call_memb_release_dtor);

__bpf_kfunc_end_defs();

-BTF_SET8_START(bpf_test_modify_return_ids)
+BTF_KFUNCS_START(bpf_test_modify_return_ids)
BTF_ID_FLAGS(func, bpf_modify_return_test)
BTF_ID_FLAGS(func, bpf_modify_return_test2)
BTF_ID_FLAGS(func, bpf_fentry_test1, KF_SLEEPABLE)
-BTF_SET8_END(bpf_test_modify_return_ids)
+BTF_KFUNCS_END(bpf_test_modify_return_ids)

static const struct btf_kfunc_id_set bpf_test_modify_return_set = {
.owner = THIS_MODULE,
.set = &bpf_test_modify_return_ids,
};

-BTF_SET8_START(test_sk_check_kfunc_ids)
+BTF_KFUNCS_START(test_sk_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_release, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_kfunc_call_memb_release, KF_RELEASE)
-BTF_SET8_END(test_sk_check_kfunc_ids)
+BTF_KFUNCS_END(test_sk_check_kfunc_ids)

static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
u32 size, u32 headroom, u32 tailroom)
diff --git a/net/core/filter.c b/net/core/filter.c
index 358870408a51..524adf1fa6d0 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -11982,21 +11982,21 @@ int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags,
return 0;
}

-BTF_SET8_START(bpf_kfunc_check_set_skb)
+BTF_KFUNCS_START(bpf_kfunc_check_set_skb)
BTF_ID_FLAGS(func, bpf_dynptr_from_skb)
-BTF_SET8_END(bpf_kfunc_check_set_skb)
+BTF_KFUNCS_END(bpf_kfunc_check_set_skb)

-BTF_SET8_START(bpf_kfunc_check_set_xdp)
+BTF_KFUNCS_START(bpf_kfunc_check_set_xdp)
BTF_ID_FLAGS(func, bpf_dynptr_from_xdp)
-BTF_SET8_END(bpf_kfunc_check_set_xdp)
+BTF_KFUNCS_END(bpf_kfunc_check_set_xdp)

-BTF_SET8_START(bpf_kfunc_check_set_sock_addr)
+BTF_KFUNCS_START(bpf_kfunc_check_set_sock_addr)
BTF_ID_FLAGS(func, bpf_sock_addr_set_sun_path)
-BTF_SET8_END(bpf_kfunc_check_set_sock_addr)
+BTF_KFUNCS_END(bpf_kfunc_check_set_sock_addr)

-BTF_SET8_START(bpf_kfunc_check_set_tcp_reqsk)
+BTF_KFUNCS_START(bpf_kfunc_check_set_tcp_reqsk)
BTF_ID_FLAGS(func, bpf_sk_assign_tcp_reqsk, KF_TRUSTED_ARGS)
-BTF_SET8_END(bpf_kfunc_check_set_tcp_reqsk)
+BTF_KFUNCS_END(bpf_kfunc_check_set_tcp_reqsk)

static const struct btf_kfunc_id_set bpf_kfunc_set_skb = {
.owner = THIS_MODULE,
@@ -12075,9 +12075,9 @@ __bpf_kfunc int bpf_sock_destroy(struct sock_common *sock)

__bpf_kfunc_end_defs();

-BTF_SET8_START(bpf_sk_iter_kfunc_ids)
+BTF_KFUNCS_START(bpf_sk_iter_kfunc_ids)
BTF_ID_FLAGS(func, bpf_sock_destroy, KF_TRUSTED_ARGS)
-BTF_SET8_END(bpf_sk_iter_kfunc_ids)
+BTF_KFUNCS_END(bpf_sk_iter_kfunc_ids)

static int tracing_iter_filter(const struct bpf_prog *prog, u32 kfunc_id)
{
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 4869c1c2d8f3..034fb80f3fbe 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -771,11 +771,11 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,

__bpf_kfunc_end_defs();

-BTF_SET8_START(xdp_metadata_kfunc_ids)
+BTF_KFUNCS_START(xdp_metadata_kfunc_ids)
#define XDP_METADATA_KFUNC(_, __, name, ___) BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS)
XDP_METADATA_KFUNC_xxx
#undef XDP_METADATA_KFUNC
-BTF_SET8_END(xdp_metadata_kfunc_ids)
+BTF_KFUNCS_END(xdp_metadata_kfunc_ids)

static const struct btf_kfunc_id_set xdp_metadata_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 834edc18463a..7f518ea5f4ac 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -201,13 +201,13 @@ bpf_tcp_ca_get_func_proto(enum bpf_func_id func_id,
}
}

-BTF_SET8_START(bpf_tcp_ca_check_kfunc_ids)
+BTF_KFUNCS_START(bpf_tcp_ca_check_kfunc_ids)
BTF_ID_FLAGS(func, tcp_reno_ssthresh)
BTF_ID_FLAGS(func, tcp_reno_cong_avoid)
BTF_ID_FLAGS(func, tcp_reno_undo_cwnd)
BTF_ID_FLAGS(func, tcp_slow_start)
BTF_ID_FLAGS(func, tcp_cong_avoid_ai)
-BTF_SET8_END(bpf_tcp_ca_check_kfunc_ids)
+BTF_KFUNCS_END(bpf_tcp_ca_check_kfunc_ids)

static const struct btf_kfunc_id_set bpf_tcp_ca_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/ipv4/fou_bpf.c b/net/ipv4/fou_bpf.c
index 4da03bf45c9b..06e5572f296f 100644
--- a/net/ipv4/fou_bpf.c
+++ b/net/ipv4/fou_bpf.c
@@ -100,10 +100,10 @@ __bpf_kfunc int bpf_skb_get_fou_encap(struct __sk_buff *skb_ctx,

__bpf_kfunc_end_defs();

-BTF_SET8_START(fou_kfunc_set)
+BTF_KFUNCS_START(fou_kfunc_set)
BTF_ID_FLAGS(func, bpf_skb_set_fou_encap)
BTF_ID_FLAGS(func, bpf_skb_get_fou_encap)
-BTF_SET8_END(fou_kfunc_set)
+BTF_KFUNCS_END(fou_kfunc_set)

static const struct btf_kfunc_id_set fou_bpf_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 22358032dd48..05dc2d05bc7c 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -1155,7 +1155,7 @@ static struct tcp_congestion_ops tcp_bbr_cong_ops __read_mostly = {
.set_state = bbr_set_state,
};

-BTF_SET8_START(tcp_bbr_check_kfunc_ids)
+BTF_KFUNCS_START(tcp_bbr_check_kfunc_ids)
#ifdef CONFIG_X86
#ifdef CONFIG_DYNAMIC_FTRACE
BTF_ID_FLAGS(func, bbr_init)
@@ -1168,7 +1168,7 @@ BTF_ID_FLAGS(func, bbr_min_tso_segs)
BTF_ID_FLAGS(func, bbr_set_state)
#endif
#endif
-BTF_SET8_END(tcp_bbr_check_kfunc_ids)
+BTF_KFUNCS_END(tcp_bbr_check_kfunc_ids)

static const struct btf_kfunc_id_set tcp_bbr_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 0fd78ecb67e7..44869ea089e3 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -485,7 +485,7 @@ static struct tcp_congestion_ops cubictcp __read_mostly = {
.name = "cubic",
};

-BTF_SET8_START(tcp_cubic_check_kfunc_ids)
+BTF_KFUNCS_START(tcp_cubic_check_kfunc_ids)
#ifdef CONFIG_X86
#ifdef CONFIG_DYNAMIC_FTRACE
BTF_ID_FLAGS(func, cubictcp_init)
@@ -496,7 +496,7 @@ BTF_ID_FLAGS(func, cubictcp_cwnd_event)
BTF_ID_FLAGS(func, cubictcp_acked)
#endif
#endif
-BTF_SET8_END(tcp_cubic_check_kfunc_ids)
+BTF_KFUNCS_END(tcp_cubic_check_kfunc_ids)

static const struct btf_kfunc_id_set tcp_cubic_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
index bb23bb5b387a..e33fbe4933e4 100644
--- a/net/ipv4/tcp_dctcp.c
+++ b/net/ipv4/tcp_dctcp.c
@@ -260,7 +260,7 @@ static struct tcp_congestion_ops dctcp_reno __read_mostly = {
.name = "dctcp-reno",
};

-BTF_SET8_START(tcp_dctcp_check_kfunc_ids)
+BTF_KFUNCS_START(tcp_dctcp_check_kfunc_ids)
#ifdef CONFIG_X86
#ifdef CONFIG_DYNAMIC_FTRACE
BTF_ID_FLAGS(func, dctcp_init)
@@ -271,7 +271,7 @@ BTF_ID_FLAGS(func, dctcp_cwnd_undo)
BTF_ID_FLAGS(func, dctcp_state)
#endif
#endif
-BTF_SET8_END(tcp_dctcp_check_kfunc_ids)
+BTF_KFUNCS_END(tcp_dctcp_check_kfunc_ids)

static const struct btf_kfunc_id_set tcp_dctcp_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index 475358ec8212..d2492d050fe6 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -467,7 +467,7 @@ __bpf_kfunc int bpf_ct_change_status(struct nf_conn *nfct, u32 status)

__bpf_kfunc_end_defs();

-BTF_SET8_START(nf_ct_kfunc_set)
+BTF_KFUNCS_START(nf_ct_kfunc_set)
BTF_ID_FLAGS(func, bpf_xdp_ct_alloc, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_xdp_ct_lookup, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_skb_ct_alloc, KF_ACQUIRE | KF_RET_NULL)
@@ -478,7 +478,7 @@ BTF_ID_FLAGS(func, bpf_ct_set_timeout, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_ct_change_timeout, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_ct_set_status, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_ct_change_status, KF_TRUSTED_ARGS)
-BTF_SET8_END(nf_ct_kfunc_set)
+BTF_KFUNCS_END(nf_ct_kfunc_set)

static const struct btf_kfunc_id_set nf_conntrack_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/netfilter/nf_nat_bpf.c b/net/netfilter/nf_nat_bpf.c
index 6e3b2f58855f..481be15609b1 100644
--- a/net/netfilter/nf_nat_bpf.c
+++ b/net/netfilter/nf_nat_bpf.c
@@ -54,9 +54,9 @@ __bpf_kfunc int bpf_ct_set_nat_info(struct nf_conn___init *nfct,

__bpf_kfunc_end_defs();

-BTF_SET8_START(nf_nat_kfunc_set)
+BTF_KFUNCS_START(nf_nat_kfunc_set)
BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
-BTF_SET8_END(nf_nat_kfunc_set)
+BTF_KFUNCS_END(nf_nat_kfunc_set)

static const struct btf_kfunc_id_set nf_bpf_nat_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c
index 7d5e920141e9..5ea15037ebd1 100644
--- a/net/xfrm/xfrm_interface_bpf.c
+++ b/net/xfrm/xfrm_interface_bpf.c
@@ -93,10 +93,10 @@ __bpf_kfunc int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx, const struct bp

__bpf_kfunc_end_defs();

-BTF_SET8_START(xfrm_ifc_kfunc_set)
+BTF_KFUNCS_START(xfrm_ifc_kfunc_set)
BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info)
BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info)
-BTF_SET8_END(xfrm_ifc_kfunc_set)
+BTF_KFUNCS_END(xfrm_ifc_kfunc_set)

static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c
index 9e20d4a377f7..2248eda741f8 100644
--- a/net/xfrm/xfrm_state_bpf.c
+++ b/net/xfrm/xfrm_state_bpf.c
@@ -117,10 +117,10 @@ __bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x)

__bpf_kfunc_end_defs();

-BTF_SET8_START(xfrm_state_kfunc_set)
+BTF_KFUNCS_START(xfrm_state_kfunc_set)
BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE)
BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE)
-BTF_SET8_END(xfrm_state_kfunc_set)
+BTF_KFUNCS_END(xfrm_state_kfunc_set)

static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = {
.owner = THIS_MODULE,
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 8befaf17d454..53f73fc86baa 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -343,12 +343,12 @@ static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = {
.write = bpf_testmod_test_write,
};

-BTF_SET8_START(bpf_testmod_common_kfunc_ids)
+BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids)
BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)
BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)
BTF_ID_FLAGS(func, bpf_kfunc_common_test)
-BTF_SET8_END(bpf_testmod_common_kfunc_ids)
+BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids)

static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {
.owner = THIS_MODULE,
@@ -494,7 +494,7 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused
return arg;
}

-BTF_SET8_START(bpf_testmod_check_kfunc_ids)
+BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
BTF_ID_FLAGS(func, bpf_kfunc_call_test2)
@@ -520,7 +520,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
-BTF_SET8_END(bpf_testmod_check_kfunc_ids)
+BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)

static int bpf_testmod_ops_init(struct btf *btf)
{
--
2.42.1

2024-01-31 09:25:05

by Benjamin Tissoires

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 3/3] bpf: treewide: Annotate BPF kfuncs in BTF

On Jan 28 2024, Daniel Xu wrote:
> This commit marks kfuncs as such inside the .BTF_ids section. The upshot
> of these annotations is that we'll be able to automatically generate
> kfunc prototypes for downstream users. The process is as follows:
>
> 1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs
> 2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for
> each function inside BTF_KFUNCS sets
> 3. At runtime, vmlinux or module BTF is made available in sysfs
> 4. At runtime, bpftool (or similar) can look at provided BTF and
> generate appropriate prototypes for functions with "bpf_kfunc" tag
>
> To ensure future kfunc are similarly tagged, we now also return error
> inside kfunc registration for untagged kfuncs. For vmlinux kfuncs,
> we also WARN(), as initcall machinery does not handle errors.
>
> Signed-off-by: Daniel Xu <[email protected]>
> ---
> Documentation/bpf/kfuncs.rst | 8 ++++----
> drivers/hid/bpf/hid_bpf_dispatch.c | 8 ++++----

For the HID changes (they shouldn't conflict with our current branch):
Acked-by: Benjamin Tissoires <[email protected]>

Cheers,
Benjamin

> fs/verity/measure.c | 4 ++--
> kernel/bpf/btf.c | 8 ++++++++
> kernel/bpf/cpumask.c | 4 ++--
> kernel/bpf/helpers.c | 8 ++++----
> kernel/bpf/map_iter.c | 4 ++--
> kernel/cgroup/rstat.c | 4 ++--
> kernel/trace/bpf_trace.c | 8 ++++----
> net/bpf/test_run.c | 8 ++++----
> net/core/filter.c | 20 +++++++++----------
> net/core/xdp.c | 4 ++--
> net/ipv4/bpf_tcp_ca.c | 4 ++--
> net/ipv4/fou_bpf.c | 4 ++--
> net/ipv4/tcp_bbr.c | 4 ++--
> net/ipv4/tcp_cubic.c | 4 ++--
> net/ipv4/tcp_dctcp.c | 4 ++--
> net/netfilter/nf_conntrack_bpf.c | 4 ++--
> net/netfilter/nf_nat_bpf.c | 4 ++--
> net/xfrm/xfrm_interface_bpf.c | 4 ++--
> net/xfrm/xfrm_state_bpf.c | 4 ++--
> .../selftests/bpf/bpf_testmod/bpf_testmod.c | 8 ++++----
> 22 files changed, 70 insertions(+), 62 deletions(-)
>
> diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst
> index 7985c6615f3c..a8f5782bd833 100644
> --- a/Documentation/bpf/kfuncs.rst
> +++ b/Documentation/bpf/kfuncs.rst
> @@ -177,10 +177,10 @@ In addition to kfuncs' arguments, verifier may need more information about the
> type of kfunc(s) being registered with the BPF subsystem. To do so, we define
> flags on a set of kfuncs as follows::
>
> - BTF_SET8_START(bpf_task_set)
> + BTF_KFUNCS_START(bpf_task_set)
> BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_put_pid, KF_RELEASE)
> - BTF_SET8_END(bpf_task_set)
> + BTF_KFUNCS_END(bpf_task_set)
>
> This set encodes the BTF ID of each kfunc listed above, and encodes the flags
> along with it. Ofcourse, it is also allowed to specify no flags.
> @@ -347,10 +347,10 @@ Once the kfunc is prepared for use, the final step to making it visible is
> registering it with the BPF subsystem. Registration is done per BPF program
> type. An example is shown below::
>
> - BTF_SET8_START(bpf_task_set)
> + BTF_KFUNCS_START(bpf_task_set)
> BTF_ID_FLAGS(func, bpf_get_task_pid, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_put_pid, KF_RELEASE)
> - BTF_SET8_END(bpf_task_set)
> + BTF_KFUNCS_END(bpf_task_set)
>
> static const struct btf_kfunc_id_set bpf_task_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c
> index d9ef45fcaeab..02c441aaa217 100644
> --- a/drivers/hid/bpf/hid_bpf_dispatch.c
> +++ b/drivers/hid/bpf/hid_bpf_dispatch.c
> @@ -172,9 +172,9 @@ hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t rdwr
> * The following set contains all functions we agree BPF programs
> * can use.
> */
> -BTF_SET8_START(hid_bpf_kfunc_ids)
> +BTF_KFUNCS_START(hid_bpf_kfunc_ids)
> BTF_ID_FLAGS(func, hid_bpf_get_data, KF_RET_NULL)
> -BTF_SET8_END(hid_bpf_kfunc_ids)
> +BTF_KFUNCS_END(hid_bpf_kfunc_ids)
>
> static const struct btf_kfunc_id_set hid_bpf_kfunc_set = {
> .owner = THIS_MODULE,
> @@ -440,12 +440,12 @@ static const struct btf_kfunc_id_set hid_bpf_fmodret_set = {
> };
>
> /* for syscall HID-BPF */
> -BTF_SET8_START(hid_bpf_syscall_kfunc_ids)
> +BTF_KFUNCS_START(hid_bpf_syscall_kfunc_ids)
> BTF_ID_FLAGS(func, hid_bpf_attach_prog)
> BTF_ID_FLAGS(func, hid_bpf_allocate_context, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, hid_bpf_release_context, KF_RELEASE)
> BTF_ID_FLAGS(func, hid_bpf_hw_request)
> -BTF_SET8_END(hid_bpf_syscall_kfunc_ids)
> +BTF_KFUNCS_END(hid_bpf_syscall_kfunc_ids)
>
> static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/fs/verity/measure.c b/fs/verity/measure.c
> index bf7a5f4cccaf..3969d54158d1 100644
> --- a/fs/verity/measure.c
> +++ b/fs/verity/measure.c
> @@ -159,9 +159,9 @@ __bpf_kfunc int bpf_get_fsverity_digest(struct file *file, struct bpf_dynptr_ker
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(fsverity_set_ids)
> +BTF_KFUNCS_START(fsverity_set_ids)
> BTF_ID_FLAGS(func, bpf_get_fsverity_digest, KF_TRUSTED_ARGS)
> -BTF_SET8_END(fsverity_set_ids)
> +BTF_KFUNCS_END(fsverity_set_ids)
>
> static int bpf_get_fsverity_digest_filter(const struct bpf_prog *prog, u32 kfunc_id)
> {
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index edef96ceffa3..bc446f37530c 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -8041,6 +8041,14 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
> {
> enum btf_kfunc_hook hook;
>
> + /* All kfuncs need to be tagged as such in BTF.
> + * WARN() for initcall registrations that do not check errors.
> + */
> + if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
> + WARN_ON(!kset->owner);
> + return -EINVAL;
> + }
> +
> hook = bpf_prog_type_to_kfunc_hook(prog_type);
> return __register_btf_kfunc_id_set(hook, kset);
> }
> diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
> index 2e73533a3811..dad0fb1c8e87 100644
> --- a/kernel/bpf/cpumask.c
> +++ b/kernel/bpf/cpumask.c
> @@ -424,7 +424,7 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(cpumask_kfunc_btf_ids)
> +BTF_KFUNCS_START(cpumask_kfunc_btf_ids)
> BTF_ID_FLAGS(func, bpf_cpumask_create, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE)
> BTF_ID_FLAGS(func, bpf_cpumask_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
> @@ -450,7 +450,7 @@ BTF_ID_FLAGS(func, bpf_cpumask_copy, KF_RCU)
> BTF_ID_FLAGS(func, bpf_cpumask_any_distribute, KF_RCU)
> BTF_ID_FLAGS(func, bpf_cpumask_any_and_distribute, KF_RCU)
> BTF_ID_FLAGS(func, bpf_cpumask_weight, KF_RCU)
> -BTF_SET8_END(cpumask_kfunc_btf_ids)
> +BTF_KFUNCS_END(cpumask_kfunc_btf_ids)
>
> static const struct btf_kfunc_id_set cpumask_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index bcb951a2ecf4..4db1c658254c 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -2544,7 +2544,7 @@ __bpf_kfunc void bpf_throw(u64 cookie)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(generic_btf_ids)
> +BTF_KFUNCS_START(generic_btf_ids)
> #ifdef CONFIG_KEXEC_CORE
> BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
> #endif
> @@ -2573,7 +2573,7 @@ BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
> #endif
> BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_throw)
> -BTF_SET8_END(generic_btf_ids)
> +BTF_KFUNCS_END(generic_btf_ids)
>
> static const struct btf_kfunc_id_set generic_kfunc_set = {
> .owner = THIS_MODULE,
> @@ -2589,7 +2589,7 @@ BTF_ID(struct, cgroup)
> BTF_ID(func, bpf_cgroup_release_dtor)
> #endif
>
> -BTF_SET8_START(common_btf_ids)
> +BTF_KFUNCS_START(common_btf_ids)
> BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx)
> BTF_ID_FLAGS(func, bpf_rdonly_cast)
> BTF_ID_FLAGS(func, bpf_rcu_read_lock)
> @@ -2618,7 +2618,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_is_null)
> BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly)
> BTF_ID_FLAGS(func, bpf_dynptr_size)
> BTF_ID_FLAGS(func, bpf_dynptr_clone)
> -BTF_SET8_END(common_btf_ids)
> +BTF_KFUNCS_END(common_btf_ids)
>
> static const struct btf_kfunc_id_set common_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
> index 6abd7c5df4b3..9575314f40a6 100644
> --- a/kernel/bpf/map_iter.c
> +++ b/kernel/bpf/map_iter.c
> @@ -213,9 +213,9 @@ __bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(bpf_map_iter_kfunc_ids)
> +BTF_KFUNCS_START(bpf_map_iter_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_map_sum_elem_count, KF_TRUSTED_ARGS)
> -BTF_SET8_END(bpf_map_iter_kfunc_ids)
> +BTF_KFUNCS_END(bpf_map_iter_kfunc_ids)
>
> static const struct btf_kfunc_id_set bpf_map_iter_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
> index a8350d2d63e6..07e2284bb499 100644
> --- a/kernel/cgroup/rstat.c
> +++ b/kernel/cgroup/rstat.c
> @@ -562,10 +562,10 @@ void cgroup_base_stat_cputime_show(struct seq_file *seq)
> }
>
> /* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */
> -BTF_SET8_START(bpf_rstat_kfunc_ids)
> +BTF_KFUNCS_START(bpf_rstat_kfunc_ids)
> BTF_ID_FLAGS(func, cgroup_rstat_updated)
> BTF_ID_FLAGS(func, cgroup_rstat_flush, KF_SLEEPABLE)
> -BTF_SET8_END(bpf_rstat_kfunc_ids)
> +BTF_KFUNCS_END(bpf_rstat_kfunc_ids)
>
> static const struct btf_kfunc_id_set bpf_rstat_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 64fdaf79d113..241ddf5e3895 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1412,14 +1412,14 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr,
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(key_sig_kfunc_set)
> +BTF_KFUNCS_START(key_sig_kfunc_set)
> BTF_ID_FLAGS(func, bpf_lookup_user_key, KF_ACQUIRE | KF_RET_NULL | KF_SLEEPABLE)
> BTF_ID_FLAGS(func, bpf_lookup_system_key, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_key_put, KF_RELEASE)
> #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
> BTF_ID_FLAGS(func, bpf_verify_pkcs7_signature, KF_SLEEPABLE)
> #endif
> -BTF_SET8_END(key_sig_kfunc_set)
> +BTF_KFUNCS_END(key_sig_kfunc_set)
>
> static const struct btf_kfunc_id_set bpf_key_sig_kfunc_set = {
> .owner = THIS_MODULE,
> @@ -1475,9 +1475,9 @@ __bpf_kfunc int bpf_get_file_xattr(struct file *file, const char *name__str,
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(fs_kfunc_set_ids)
> +BTF_KFUNCS_START(fs_kfunc_set_ids)
> BTF_ID_FLAGS(func, bpf_get_file_xattr, KF_SLEEPABLE | KF_TRUSTED_ARGS)
> -BTF_SET8_END(fs_kfunc_set_ids)
> +BTF_KFUNCS_END(fs_kfunc_set_ids)
>
> static int bpf_get_file_xattr_filter(const struct bpf_prog *prog, u32 kfunc_id)
> {
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index dfd919374017..5535f9adc658 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -617,21 +617,21 @@ CFI_NOSEAL(bpf_kfunc_call_memb_release_dtor);
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(bpf_test_modify_return_ids)
> +BTF_KFUNCS_START(bpf_test_modify_return_ids)
> BTF_ID_FLAGS(func, bpf_modify_return_test)
> BTF_ID_FLAGS(func, bpf_modify_return_test2)
> BTF_ID_FLAGS(func, bpf_fentry_test1, KF_SLEEPABLE)
> -BTF_SET8_END(bpf_test_modify_return_ids)
> +BTF_KFUNCS_END(bpf_test_modify_return_ids)
>
> static const struct btf_kfunc_id_set bpf_test_modify_return_set = {
> .owner = THIS_MODULE,
> .set = &bpf_test_modify_return_ids,
> };
>
> -BTF_SET8_START(test_sk_check_kfunc_ids)
> +BTF_KFUNCS_START(test_sk_check_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test_release, KF_RELEASE)
> BTF_ID_FLAGS(func, bpf_kfunc_call_memb_release, KF_RELEASE)
> -BTF_SET8_END(test_sk_check_kfunc_ids)
> +BTF_KFUNCS_END(test_sk_check_kfunc_ids)
>
> static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
> u32 size, u32 headroom, u32 tailroom)
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 358870408a51..524adf1fa6d0 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -11982,21 +11982,21 @@ int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags,
> return 0;
> }
>
> -BTF_SET8_START(bpf_kfunc_check_set_skb)
> +BTF_KFUNCS_START(bpf_kfunc_check_set_skb)
> BTF_ID_FLAGS(func, bpf_dynptr_from_skb)
> -BTF_SET8_END(bpf_kfunc_check_set_skb)
> +BTF_KFUNCS_END(bpf_kfunc_check_set_skb)
>
> -BTF_SET8_START(bpf_kfunc_check_set_xdp)
> +BTF_KFUNCS_START(bpf_kfunc_check_set_xdp)
> BTF_ID_FLAGS(func, bpf_dynptr_from_xdp)
> -BTF_SET8_END(bpf_kfunc_check_set_xdp)
> +BTF_KFUNCS_END(bpf_kfunc_check_set_xdp)
>
> -BTF_SET8_START(bpf_kfunc_check_set_sock_addr)
> +BTF_KFUNCS_START(bpf_kfunc_check_set_sock_addr)
> BTF_ID_FLAGS(func, bpf_sock_addr_set_sun_path)
> -BTF_SET8_END(bpf_kfunc_check_set_sock_addr)
> +BTF_KFUNCS_END(bpf_kfunc_check_set_sock_addr)
>
> -BTF_SET8_START(bpf_kfunc_check_set_tcp_reqsk)
> +BTF_KFUNCS_START(bpf_kfunc_check_set_tcp_reqsk)
> BTF_ID_FLAGS(func, bpf_sk_assign_tcp_reqsk, KF_TRUSTED_ARGS)
> -BTF_SET8_END(bpf_kfunc_check_set_tcp_reqsk)
> +BTF_KFUNCS_END(bpf_kfunc_check_set_tcp_reqsk)
>
> static const struct btf_kfunc_id_set bpf_kfunc_set_skb = {
> .owner = THIS_MODULE,
> @@ -12075,9 +12075,9 @@ __bpf_kfunc int bpf_sock_destroy(struct sock_common *sock)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(bpf_sk_iter_kfunc_ids)
> +BTF_KFUNCS_START(bpf_sk_iter_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_sock_destroy, KF_TRUSTED_ARGS)
> -BTF_SET8_END(bpf_sk_iter_kfunc_ids)
> +BTF_KFUNCS_END(bpf_sk_iter_kfunc_ids)
>
> static int tracing_iter_filter(const struct bpf_prog *prog, u32 kfunc_id)
> {
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 4869c1c2d8f3..034fb80f3fbe 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -771,11 +771,11 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(xdp_metadata_kfunc_ids)
> +BTF_KFUNCS_START(xdp_metadata_kfunc_ids)
> #define XDP_METADATA_KFUNC(_, __, name, ___) BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS)
> XDP_METADATA_KFUNC_xxx
> #undef XDP_METADATA_KFUNC
> -BTF_SET8_END(xdp_metadata_kfunc_ids)
> +BTF_KFUNCS_END(xdp_metadata_kfunc_ids)
>
> static const struct btf_kfunc_id_set xdp_metadata_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
> index 834edc18463a..7f518ea5f4ac 100644
> --- a/net/ipv4/bpf_tcp_ca.c
> +++ b/net/ipv4/bpf_tcp_ca.c
> @@ -201,13 +201,13 @@ bpf_tcp_ca_get_func_proto(enum bpf_func_id func_id,
> }
> }
>
> -BTF_SET8_START(bpf_tcp_ca_check_kfunc_ids)
> +BTF_KFUNCS_START(bpf_tcp_ca_check_kfunc_ids)
> BTF_ID_FLAGS(func, tcp_reno_ssthresh)
> BTF_ID_FLAGS(func, tcp_reno_cong_avoid)
> BTF_ID_FLAGS(func, tcp_reno_undo_cwnd)
> BTF_ID_FLAGS(func, tcp_slow_start)
> BTF_ID_FLAGS(func, tcp_cong_avoid_ai)
> -BTF_SET8_END(bpf_tcp_ca_check_kfunc_ids)
> +BTF_KFUNCS_END(bpf_tcp_ca_check_kfunc_ids)
>
> static const struct btf_kfunc_id_set bpf_tcp_ca_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/ipv4/fou_bpf.c b/net/ipv4/fou_bpf.c
> index 4da03bf45c9b..06e5572f296f 100644
> --- a/net/ipv4/fou_bpf.c
> +++ b/net/ipv4/fou_bpf.c
> @@ -100,10 +100,10 @@ __bpf_kfunc int bpf_skb_get_fou_encap(struct __sk_buff *skb_ctx,
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(fou_kfunc_set)
> +BTF_KFUNCS_START(fou_kfunc_set)
> BTF_ID_FLAGS(func, bpf_skb_set_fou_encap)
> BTF_ID_FLAGS(func, bpf_skb_get_fou_encap)
> -BTF_SET8_END(fou_kfunc_set)
> +BTF_KFUNCS_END(fou_kfunc_set)
>
> static const struct btf_kfunc_id_set fou_bpf_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
> index 22358032dd48..05dc2d05bc7c 100644
> --- a/net/ipv4/tcp_bbr.c
> +++ b/net/ipv4/tcp_bbr.c
> @@ -1155,7 +1155,7 @@ static struct tcp_congestion_ops tcp_bbr_cong_ops __read_mostly = {
> .set_state = bbr_set_state,
> };
>
> -BTF_SET8_START(tcp_bbr_check_kfunc_ids)
> +BTF_KFUNCS_START(tcp_bbr_check_kfunc_ids)
> #ifdef CONFIG_X86
> #ifdef CONFIG_DYNAMIC_FTRACE
> BTF_ID_FLAGS(func, bbr_init)
> @@ -1168,7 +1168,7 @@ BTF_ID_FLAGS(func, bbr_min_tso_segs)
> BTF_ID_FLAGS(func, bbr_set_state)
> #endif
> #endif
> -BTF_SET8_END(tcp_bbr_check_kfunc_ids)
> +BTF_KFUNCS_END(tcp_bbr_check_kfunc_ids)
>
> static const struct btf_kfunc_id_set tcp_bbr_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
> index 0fd78ecb67e7..44869ea089e3 100644
> --- a/net/ipv4/tcp_cubic.c
> +++ b/net/ipv4/tcp_cubic.c
> @@ -485,7 +485,7 @@ static struct tcp_congestion_ops cubictcp __read_mostly = {
> .name = "cubic",
> };
>
> -BTF_SET8_START(tcp_cubic_check_kfunc_ids)
> +BTF_KFUNCS_START(tcp_cubic_check_kfunc_ids)
> #ifdef CONFIG_X86
> #ifdef CONFIG_DYNAMIC_FTRACE
> BTF_ID_FLAGS(func, cubictcp_init)
> @@ -496,7 +496,7 @@ BTF_ID_FLAGS(func, cubictcp_cwnd_event)
> BTF_ID_FLAGS(func, cubictcp_acked)
> #endif
> #endif
> -BTF_SET8_END(tcp_cubic_check_kfunc_ids)
> +BTF_KFUNCS_END(tcp_cubic_check_kfunc_ids)
>
> static const struct btf_kfunc_id_set tcp_cubic_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c
> index bb23bb5b387a..e33fbe4933e4 100644
> --- a/net/ipv4/tcp_dctcp.c
> +++ b/net/ipv4/tcp_dctcp.c
> @@ -260,7 +260,7 @@ static struct tcp_congestion_ops dctcp_reno __read_mostly = {
> .name = "dctcp-reno",
> };
>
> -BTF_SET8_START(tcp_dctcp_check_kfunc_ids)
> +BTF_KFUNCS_START(tcp_dctcp_check_kfunc_ids)
> #ifdef CONFIG_X86
> #ifdef CONFIG_DYNAMIC_FTRACE
> BTF_ID_FLAGS(func, dctcp_init)
> @@ -271,7 +271,7 @@ BTF_ID_FLAGS(func, dctcp_cwnd_undo)
> BTF_ID_FLAGS(func, dctcp_state)
> #endif
> #endif
> -BTF_SET8_END(tcp_dctcp_check_kfunc_ids)
> +BTF_KFUNCS_END(tcp_dctcp_check_kfunc_ids)
>
> static const struct btf_kfunc_id_set tcp_dctcp_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
> index 475358ec8212..d2492d050fe6 100644
> --- a/net/netfilter/nf_conntrack_bpf.c
> +++ b/net/netfilter/nf_conntrack_bpf.c
> @@ -467,7 +467,7 @@ __bpf_kfunc int bpf_ct_change_status(struct nf_conn *nfct, u32 status)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(nf_ct_kfunc_set)
> +BTF_KFUNCS_START(nf_ct_kfunc_set)
> BTF_ID_FLAGS(func, bpf_xdp_ct_alloc, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_xdp_ct_lookup, KF_ACQUIRE | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_skb_ct_alloc, KF_ACQUIRE | KF_RET_NULL)
> @@ -478,7 +478,7 @@ BTF_ID_FLAGS(func, bpf_ct_set_timeout, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_change_timeout, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_set_status, KF_TRUSTED_ARGS)
> BTF_ID_FLAGS(func, bpf_ct_change_status, KF_TRUSTED_ARGS)
> -BTF_SET8_END(nf_ct_kfunc_set)
> +BTF_KFUNCS_END(nf_ct_kfunc_set)
>
> static const struct btf_kfunc_id_set nf_conntrack_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/netfilter/nf_nat_bpf.c b/net/netfilter/nf_nat_bpf.c
> index 6e3b2f58855f..481be15609b1 100644
> --- a/net/netfilter/nf_nat_bpf.c
> +++ b/net/netfilter/nf_nat_bpf.c
> @@ -54,9 +54,9 @@ __bpf_kfunc int bpf_ct_set_nat_info(struct nf_conn___init *nfct,
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(nf_nat_kfunc_set)
> +BTF_KFUNCS_START(nf_nat_kfunc_set)
> BTF_ID_FLAGS(func, bpf_ct_set_nat_info, KF_TRUSTED_ARGS)
> -BTF_SET8_END(nf_nat_kfunc_set)
> +BTF_KFUNCS_END(nf_nat_kfunc_set)
>
> static const struct btf_kfunc_id_set nf_bpf_nat_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c
> index 7d5e920141e9..5ea15037ebd1 100644
> --- a/net/xfrm/xfrm_interface_bpf.c
> +++ b/net/xfrm/xfrm_interface_bpf.c
> @@ -93,10 +93,10 @@ __bpf_kfunc int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx, const struct bp
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(xfrm_ifc_kfunc_set)
> +BTF_KFUNCS_START(xfrm_ifc_kfunc_set)
> BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info)
> BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info)
> -BTF_SET8_END(xfrm_ifc_kfunc_set)
> +BTF_KFUNCS_END(xfrm_ifc_kfunc_set)
>
> static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c
> index 9e20d4a377f7..2248eda741f8 100644
> --- a/net/xfrm/xfrm_state_bpf.c
> +++ b/net/xfrm/xfrm_state_bpf.c
> @@ -117,10 +117,10 @@ __bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x)
>
> __bpf_kfunc_end_defs();
>
> -BTF_SET8_START(xfrm_state_kfunc_set)
> +BTF_KFUNCS_START(xfrm_state_kfunc_set)
> BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE)
> BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE)
> -BTF_SET8_END(xfrm_state_kfunc_set)
> +BTF_KFUNCS_END(xfrm_state_kfunc_set)
>
> static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = {
> .owner = THIS_MODULE,
> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> index 8befaf17d454..53f73fc86baa 100644
> --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> @@ -343,12 +343,12 @@ static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = {
> .write = bpf_testmod_test_write,
> };
>
> -BTF_SET8_START(bpf_testmod_common_kfunc_ids)
> +BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)
> BTF_ID_FLAGS(func, bpf_kfunc_common_test)
> -BTF_SET8_END(bpf_testmod_common_kfunc_ids)
> +BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids)
>
> static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {
> .owner = THIS_MODULE,
> @@ -494,7 +494,7 @@ __bpf_kfunc static u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused
> return arg;
> }
>
> -BTF_SET8_START(bpf_testmod_check_kfunc_ids)
> +BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test2)
> @@ -520,7 +520,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS | KF_RCU)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
> BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
> -BTF_SET8_END(bpf_testmod_check_kfunc_ids)
> +BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
>
> static int bpf_testmod_ops_init(struct btf *btf)
> {
> --
> 2.42.1
>

2024-01-31 09:51:49

by Jiri Olsa

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

2024-01-31 20:23:26

by patchwork-bot+netdevbpf

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <[email protected]>:

On Sun, 28 Jan 2024 18:24:05 -0700 you wrote:
> === Description ===
>
> This is a bpf-treewide change that annotates all kfuncs as such inside
> .BTF_ids. This annotation eventually allows us to automatically generate
> kfunc prototypes from bpftool.
>
> We store this metadata inside a yet-unused flags field inside struct
> btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
>
> [...]

Here is the summary with links:
- [bpf-next,v4,1/3] bpf: btf: Support flags for BTF_SET8 sets
https://git.kernel.org/bpf/bpf-next/c/79b47344bbc5
- [bpf-next,v4,2/3] bpf: btf: Add BTF_KFUNCS_START/END macro pair
https://git.kernel.org/bpf/bpf-next/c/2747e0ee57c2
- [bpf-next,v4,3/3] bpf: treewide: Annotate BPF kfuncs in BTF
https://git.kernel.org/bpf/bpf-next/c/6e7769e6419f

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

2024-02-02 23:09:32

by Manu Bretelle

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

On Sun, Jan 28, 2024 at 06:24:05PM -0700, Daniel Xu wrote:
> === Description ===
>
> This is a bpf-treewide change that annotates all kfuncs as such inside
> .BTF_ids. This annotation eventually allows us to automatically generate
> kfunc prototypes from bpftool.
>
> We store this metadata inside a yet-unused flags field inside struct
> btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
>
> More details about the full chain of events are available in commit 3's
> description.
>
> The accompanying pahole and bpftool changes can be viewed
> here on these "frozen" branches [0][1].
>
> [0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
> [1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed

I hit a similar issue to [0] on master
943b043aeecc ("selftests/bpf: Fix bench runner SIGSEGV")
when cross-compiling on x86_64 (LE) to s390x (BE).
I do have CONFIG_DEBUG_INFO_BTF enable and the issue would not trigger if
I disabled CONFIG_DEBUG_INFO_BTF (and with the fix mentioned in [0]).

What seems to happen is that `tools/resolve_btfids` is ran in the context of the
host endianess and if I printk before the WARN_ON:
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ef380e546952..a9ed7a1a4936 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -8128,6 +8128,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
* WARN() for initcall registrations that do not check errors.
*/
if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
+ printk("Flag 0x%08X, expected 0x%08X\n", kset->set->flags, BTF_SET8_KFUNCS);
WARN_ON(!kset->owner);
return -EINVAL;
}

the boot logs would show:
Flag 0x01000000, expected 0x00000001

The issue did not happen prior to
6f3189f38a3e ("bpf: treewide: Annotate BPF kfuncs in BTF")
has only 0 was written before.

It seems [1] will be addressing cross-compilation, but it did not fix it as is
by just applying on top of master, so probably some of the changes will also need
to be ported to `tools/include/linux/btf_ids.h`?

A hacky workaround to cross-compilation I have is to apply:

diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 4b8079f294f6..b706e7ab066f 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -22,10 +22,10 @@ HOST_OVERRIDES := AR="$(HOSTAR)" CC="$(HOSTCC)" LD="$(HOSTLD)" ARCH="$(HOSTARCH)
CROSS_COMPILE="" EXTRA_CFLAGS="$(HOSTCFLAGS)"
RM ?= rm
-HOSTCC ?= gcc
-HOSTLD ?= ld
-HOSTAR ?= ar
-CROSS_COMPILE =
+HOSTCC = $(CC)
+HOSTLD = $(LD)
+HOSTAR = $(AR)
+#CROSS_COMPILE =
OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
@@ -56,16 +56,16 @@ $(OUTPUT) $(OUTPUT)/libsubcmd $(LIBBPF_OUT):
$(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(SUBCMD_OUT) \
- DESTDIR=$(SUBCMD_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
+ DESTDIR=$(SUBCMD_DESTDIR) prefix= subdir= \
$(abspath $@) install_headers
$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUT)
$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT) \
- DESTDIR=$(LIBBPF_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
+ DESTDIR=$(LIBBPF_DESTDIR) prefix= subdir= \
$(abspath $@) install_headers
-LIBELF_FLAGS := $(shell $(HOSTPKG_CONFIG) libelf --cflags 2>/dev/null)
-LIBELF_LIBS := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
+LIBELF_FLAGS := $(shell $(PKG_CONFIG) libelf --cflags 2>/dev/null)
+LIBELF_LIBS := $(shell $(PKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
HOSTCFLAGS_resolve_btfids += -g \
-I$(srctree)/tools/include \
@@ -84,7 +84,7 @@ $(BINARY_IN): fixdep FORCE prepare | $(OUTPUT)
$(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
$(call msg,LINK,$@)
- $(Q)$(HOSTCC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
+ $(Q)$(CC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
clean_objects := $(wildcard $(OUTPUT)/*.o \
$(OUTPUT)/.*.o.cmd \
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index a38a3001527c..5cd193c04448 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -171,7 +171,7 @@ INCLUDE_DIR := $(SCRATCH_DIR)/include
BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
ifneq ($(CROSS_COMPILE),)
HOST_BUILD_DIR := $(BUILD_DIR)/host
-HOST_SCRATCH_DIR := $(OUTPUT)/host-tools
+HOST_SCRATCH_DIR := $(SCRATCH_DIR)
HOST_INCLUDE_DIR := $(HOST_SCRATCH_DIR)/include
else
HOST_BUILD_DIR := $(BUILD_DIR)

This causes `resolve_btfids` to be compiled in the target endianess and gets
magically run provided that the hosts has `qemu-s390x-static` and a functional
binfmt_misc [2] on the host, but having this using host architecture per [1]
is likely better.

Here are steps to reproduce the issue on Ubuntu 23.10 and assuming
danobi/vmtest [3] is installed:

XPLATFORM="s390x"
XARCH="s390"
# Set up repo for s390x
cat <<EOF >> /etc/apt/sources.list.d/s390x.list
deb [arch=s390x] http://ports.ubuntu.com/ubuntu-ports mantic main restricted
deb [arch=s390x] http://ports.ubuntu.com/ubuntu-ports mantic-updates main restricted
EOF
sudo dpkg --add-architecture s390x

apt install qemu-system-s390x qemu-user-static g{cc,++}-"${XARCH}-linux-gnu" {libelf-dev,libssl-dev,pkgconf}:s390x

KBUILD_OUTPUT_DIR="/tmp/kbuild-${XPLATFORM}"
mkdir "${KBUILD_OUTPUT_DIR}"
cat tools/testing/selftests/bpf/config{,.vm,.${XPLATFORM}} > ${KBUILD_OUTPUT_DIR}/.config

make ARCH="${XARCH}" CROSS_COMPILE="${XPLATFORM}-linux-gnu-" O="${KBUILD_OUTPUT_DIR}" -j$((4 * $(nproc))) olddefconfig
make ARCH="${XARCH}" CROSS_COMPILE="${XPLATFORM}-linux-gnu-" O="${KBUILD_OUTPUT_DIR}" -j$((4 * $(nproc))) all

# No need for a s390x ubuntu 23.10 rootfs, we only care about booting the kernel
vmtest -k "${KBUILD_OUTPUT_DIR}/arch/s390/boot/bzImage" -a s390x "uname -m" | cat

For the chroot route, see [4].

[0] https://lore.kernel.org/linux-kernel/[email protected]/T/
[1] https://lore.kernel.org/bpf/[email protected]/
[2] https://en.wikipedia.org/wiki/Binfmt_misc
[3] https://github.com/danobi/vmtest
[4] https://chantra.github.io/bpfcitools/bpf-cross-compile.html

Manu

>
> === Changelog ===
>
> Changes from v3:
> * Rebase to bpf-next and add missing annotation on new kfunc
>
> Changes from v2:
> * Only WARN() for vmlinux kfuncs
>
> Changes from v1:
> * Move WARN_ON() up a call level
> * Also return error when kfunc set is not properly tagged
> * Use BTF_KFUNCS_START/END instead of flags
> * Rename BTF_SET8_KFUNC to BTF_SET8_KFUNCS
>
> Daniel Xu (3):
> bpf: btf: Support flags for BTF_SET8 sets
> bpf: btf: Add BTF_KFUNCS_START/END macro pair
> bpf: treewide: Annotate BPF kfuncs in BTF
>
> Documentation/bpf/kfuncs.rst | 8 +++----
> drivers/hid/bpf/hid_bpf_dispatch.c | 8 +++----
> fs/verity/measure.c | 4 ++--
> include/linux/btf_ids.h | 21 +++++++++++++++----
> kernel/bpf/btf.c | 8 +++++++
> kernel/bpf/cpumask.c | 4 ++--
> kernel/bpf/helpers.c | 8 +++----
> kernel/bpf/map_iter.c | 4 ++--
> kernel/cgroup/rstat.c | 4 ++--
> kernel/trace/bpf_trace.c | 8 +++----
> net/bpf/test_run.c | 8 +++----
> net/core/filter.c | 20 +++++++++---------
> net/core/xdp.c | 4 ++--
> net/ipv4/bpf_tcp_ca.c | 4 ++--
> net/ipv4/fou_bpf.c | 4 ++--
> net/ipv4/tcp_bbr.c | 4 ++--
> net/ipv4/tcp_cubic.c | 4 ++--
> net/ipv4/tcp_dctcp.c | 4 ++--
> net/netfilter/nf_conntrack_bpf.c | 4 ++--
> net/netfilter/nf_nat_bpf.c | 4 ++--
> net/xfrm/xfrm_interface_bpf.c | 4 ++--
> net/xfrm/xfrm_state_bpf.c | 4 ++--
> .../selftests/bpf/bpf_testmod/bpf_testmod.c | 8 +++----
> 23 files changed, 87 insertions(+), 66 deletions(-)
>
> --
> 2.42.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

2024-02-03 01:35:13

by Daniel Xu

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

Hi Manu,

On Fri, Feb 02, 2024 at 03:09:05PM -0800, Manu Bretelle wrote:
> On Sun, Jan 28, 2024 at 06:24:05PM -0700, Daniel Xu wrote:
> > === Description ===
> >
> > This is a bpf-treewide change that annotates all kfuncs as such inside
> > .BTF_ids. This annotation eventually allows us to automatically generate
> > kfunc prototypes from bpftool.
> >
> > We store this metadata inside a yet-unused flags field inside struct
> > btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
> >
> > More details about the full chain of events are available in commit 3's
> > description.
> >
> > The accompanying pahole and bpftool changes can be viewed
> > here on these "frozen" branches [0][1].
> >
> > [0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
> > [1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed
>
>
> I hit a similar issue to [0] on master
> 943b043aeecc ("selftests/bpf: Fix bench runner SIGSEGV")
> when cross-compiling on x86_64 (LE) to s390x (BE).
> I do have CONFIG_DEBUG_INFO_BTF enable and the issue would not trigger if
> I disabled CONFIG_DEBUG_INFO_BTF (and with the fix mentioned in [0]).
>
> What seems to happen is that `tools/resolve_btfids` is ran in the context of the
> host endianess and if I printk before the WARN_ON:
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index ef380e546952..a9ed7a1a4936 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -8128,6 +8128,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
> * WARN() for initcall registrations that do not check errors.
> */
> if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
> + printk("Flag 0x%08X, expected 0x%08X\n", kset->set->flags, BTF_SET8_KFUNCS);
> WARN_ON(!kset->owner);
> return -EINVAL;
> }
>
> the boot logs would show:
> Flag 0x01000000, expected 0x00000001
>
> The issue did not happen prior to
> 6f3189f38a3e ("bpf: treewide: Annotate BPF kfuncs in BTF")
> has only 0 was written before.
>
> It seems [1] will be addressing cross-compilation, but it did not fix it as is
> by just applying on top of master, so probably some of the changes will also need
> to be ported to `tools/include/linux/btf_ids.h`?
>
> A hacky workaround to cross-compilation I have is to apply:
>
> diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
> index 4b8079f294f6..b706e7ab066f 100644
> --- a/tools/bpf/resolve_btfids/Makefile
> +++ b/tools/bpf/resolve_btfids/Makefile
> @@ -22,10 +22,10 @@ HOST_OVERRIDES := AR="$(HOSTAR)" CC="$(HOSTCC)" LD="$(HOSTLD)" ARCH="$(HOSTARCH)
> CROSS_COMPILE="" EXTRA_CFLAGS="$(HOSTCFLAGS)"
> RM ?= rm
> -HOSTCC ?= gcc
> -HOSTLD ?= ld
> -HOSTAR ?= ar
> -CROSS_COMPILE =
> +HOSTCC = $(CC)
> +HOSTLD = $(LD)
> +HOSTAR = $(AR)
> +#CROSS_COMPILE =
> OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
> @@ -56,16 +56,16 @@ $(OUTPUT) $(OUTPUT)/libsubcmd $(LIBBPF_OUT):
> $(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
> $(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(SUBCMD_OUT) \
> - DESTDIR=$(SUBCMD_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
> + DESTDIR=$(SUBCMD_DESTDIR) prefix= subdir= \
> $(abspath $@) install_headers
> $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUT)
> $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT) \
> - DESTDIR=$(LIBBPF_DESTDIR) $(HOST_OVERRIDES) prefix= subdir= \
> + DESTDIR=$(LIBBPF_DESTDIR) prefix= subdir= \
> $(abspath $@) install_headers
> -LIBELF_FLAGS := $(shell $(HOSTPKG_CONFIG) libelf --cflags 2>/dev/null)
> -LIBELF_LIBS := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
> +LIBELF_FLAGS := $(shell $(PKG_CONFIG) libelf --cflags 2>/dev/null)
> +LIBELF_LIBS := $(shell $(PKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
> HOSTCFLAGS_resolve_btfids += -g \
> -I$(srctree)/tools/include \
> @@ -84,7 +84,7 @@ $(BINARY_IN): fixdep FORCE prepare | $(OUTPUT)
> $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
> $(call msg,LINK,$@)
> - $(Q)$(HOSTCC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
> + $(Q)$(CC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
> clean_objects := $(wildcard $(OUTPUT)/*.o \
> $(OUTPUT)/.*.o.cmd \
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index a38a3001527c..5cd193c04448 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -171,7 +171,7 @@ INCLUDE_DIR := $(SCRATCH_DIR)/include
> BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
> ifneq ($(CROSS_COMPILE),)
> HOST_BUILD_DIR := $(BUILD_DIR)/host
> -HOST_SCRATCH_DIR := $(OUTPUT)/host-tools
> +HOST_SCRATCH_DIR := $(SCRATCH_DIR)
> HOST_INCLUDE_DIR := $(HOST_SCRATCH_DIR)/include
> else
> HOST_BUILD_DIR := $(BUILD_DIR)
>
> This causes `resolve_btfids` to be compiled in the target endianess and gets
> magically run provided that the hosts has `qemu-s390x-static` and a functional
> binfmt_misc [2] on the host, but having this using host architecture per [1]
> is likely better.

This is kinda surprising to me. I don't recall seeing any code inside
resolve_btfids that touches the set8 flags field -- only the ids in the
flexible array member. Would be interested to see what the value of the
set8 flags field is before resolve_btfids is run.

I'm a bit busy until Sunday afternoon but I'll try to take a look around
then. Might be a good opportunity to play with poke [0].

Thanks,
Daniel

[0]: http://www.jemarch.net/poke

2024-02-03 14:41:57

by Jiri Olsa

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

On Fri, Feb 02, 2024 at 03:09:05PM -0800, Manu Bretelle wrote:
> On Sun, Jan 28, 2024 at 06:24:05PM -0700, Daniel Xu wrote:
> > === Description ===
> >
> > This is a bpf-treewide change that annotates all kfuncs as such inside
> > .BTF_ids. This annotation eventually allows us to automatically generate
> > kfunc prototypes from bpftool.
> >
> > We store this metadata inside a yet-unused flags field inside struct
> > btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
> >
> > More details about the full chain of events are available in commit 3's
> > description.
> >
> > The accompanying pahole and bpftool changes can be viewed
> > here on these "frozen" branches [0][1].
> >
> > [0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
> > [1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed
>
>
> I hit a similar issue to [0] on master
> 943b043aeecc ("selftests/bpf: Fix bench runner SIGSEGV")
> when cross-compiling on x86_64 (LE) to s390x (BE).
> I do have CONFIG_DEBUG_INFO_BTF enable and the issue would not trigger if
> I disabled CONFIG_DEBUG_INFO_BTF (and with the fix mentioned in [0]).
>
> What seems to happen is that `tools/resolve_btfids` is ran in the context of the
> host endianess and if I printk before the WARN_ON:
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index ef380e546952..a9ed7a1a4936 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -8128,6 +8128,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
> * WARN() for initcall registrations that do not check errors.
> */
> if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
> + printk("Flag 0x%08X, expected 0x%08X\n", kset->set->flags, BTF_SET8_KFUNCS);
> WARN_ON(!kset->owner);
> return -EINVAL;
> }
>
> the boot logs would show:
> Flag 0x01000000, expected 0x00000001
>
> The issue did not happen prior to
> 6f3189f38a3e ("bpf: treewide: Annotate BPF kfuncs in BTF")
> has only 0 was written before.
>
> It seems [1] will be addressing cross-compilation, but it did not fix it as is
> by just applying on top of master, so probably some of the changes will also need
> to be ported to `tools/include/linux/btf_ids.h`?

the fix in [1] is fixing flags in set8's pairs, but not the global flags

it looks like Viktor's fix should now also swap that as well? like in the
change below on top of Viktor's changes (untested)

jirka

---
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index d01603ef6283..c44d57fec390 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -706,6 +706,8 @@ static int sets_patch(struct object *obj)
* correctly translate everything.
*/
if (need_bswap) {
+ set8->flags = bswap_32(set8->flags);
+
for (i = 0; i < cnt; i++) {
set8->pairs[i].flags =
bswap_32(set8->pairs[i].flags);

2024-02-03 18:48:02

by Manu Bretelle

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

On Sat, Feb 03, 2024 at 03:40:24PM +0100, Jiri Olsa wrote:
> On Fri, Feb 02, 2024 at 03:09:05PM -0800, Manu Bretelle wrote:
> > On Sun, Jan 28, 2024 at 06:24:05PM -0700, Daniel Xu wrote:
> > > === Description ===
> > >
> > > This is a bpf-treewide change that annotates all kfuncs as such inside
> > > .BTF_ids. This annotation eventually allows us to automatically generate
> > > kfunc prototypes from bpftool.
> > >
> > > We store this metadata inside a yet-unused flags field inside struct
> > > btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
> > >
> > > More details about the full chain of events are available in commit 3's
> > > description.
> > >
> > > The accompanying pahole and bpftool changes can be viewed
> > > here on these "frozen" branches [0][1].
> > >
> > > [0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
> > > [1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed
> >
> >
> > I hit a similar issue to [0] on master
> > 943b043aeecc ("selftests/bpf: Fix bench runner SIGSEGV")
> > when cross-compiling on x86_64 (LE) to s390x (BE).
> > I do have CONFIG_DEBUG_INFO_BTF enable and the issue would not trigger if
> > I disabled CONFIG_DEBUG_INFO_BTF (and with the fix mentioned in [0]).
> >
> > What seems to happen is that `tools/resolve_btfids` is ran in the context of the
> > host endianess and if I printk before the WARN_ON:
> > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> > index ef380e546952..a9ed7a1a4936 100644
> > --- a/kernel/bpf/btf.c
> > +++ b/kernel/bpf/btf.c
> > @@ -8128,6 +8128,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
> > * WARN() for initcall registrations that do not check errors.
> > */
> > if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
> > + printk("Flag 0x%08X, expected 0x%08X\n", kset->set->flags, BTF_SET8_KFUNCS);
> > WARN_ON(!kset->owner);
> > return -EINVAL;
> > }
> >
> > the boot logs would show:
> > Flag 0x01000000, expected 0x00000001
> >
> > The issue did not happen prior to
> > 6f3189f38a3e ("bpf: treewide: Annotate BPF kfuncs in BTF")
> > has only 0 was written before.
> >
> > It seems [1] will be addressing cross-compilation, but it did not fix it as is
> > by just applying on top of master, so probably some of the changes will also need
> > to be ported to `tools/include/linux/btf_ids.h`?
>
> the fix in [1] is fixing flags in set8's pairs, but not the global flags
>
> it looks like Viktor's fix should now also swap that as well? like in the
> change below on top of Viktor's changes (untested)
>
> jirka
>
>
> ---
> diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
> index d01603ef6283..c44d57fec390 100644
> --- a/tools/bpf/resolve_btfids/main.c
> +++ b/tools/bpf/resolve_btfids/main.c
> @@ -706,6 +706,8 @@ static int sets_patch(struct object *obj)
> * correctly translate everything.
> */
> if (need_bswap) {
> + set8->flags = bswap_32(set8->flags);
> +
> for (i = 0; i < cnt; i++) {
> set8->pairs[i].flags =
> bswap_32(set8->pairs[i].flags);
>

That should work. Here are a few tests I ran:

$ md5sum /tmp/kbuild-s390x/vmlinux.*
eb658e51e089f3c5b2c8909a29dc9997 /tmp/kbuild-s390x/vmlinux.a
# plain vmlinux before running resolv_btfids (all 0s)
ea907cd46a1a73b8276b5f2a82af00ca /tmp/kbuild-s390x/vmlinux.before_resolv
# x86_64 resolv_btfids on master without Viktor's patch
980a40c3a3ff563d1c2d1ebdd5071a23 /tmp/kbuild-s390x/vmlinux.resolv_native
# x86_64 resolv_btfids on master with Viktor's patch
b986d19e242719ebea41c578235da662 /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor
# x86_64 resolv_btfids on master with Viktor's patch and your suggested patch
4edd8752ff01129945bd442689b1927b /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor_patched
# s390x resolv_btfids run with qemu-s390x-static
4edd8752ff01129945bd442689b1927b /tmp/kbuild-s390x/vmlinux.resolv_s390x

and some hexdiff of those binaries:

# difference between master's native build and s390x build.... has byte swapping for set8 and others
diff -ruN <(xxd /tmp/kbuild-s390x/vmlinux.resolv_s390x) <(xxd /tmp/kbuild-s390x/vmlinux.resolv_native) > diff_s390x_native.diff
https://gist.github.com/chantra/c3d58637a08a6f7340953dc155bb18cc

# difference betwee Viktor's version and s390x build.... squinting my eyes I only see the global set8 is missing
diff -ruN <(xxd /tmp/kbuild-s390x/vmlinux.resolv_s390x) <(xxd /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor) > diff_s390x_native_viktor.diff
https://gist.github.com/chantra/61cfff02b456ae72d3c0161ce1897097

Have a good weekend all!

Manu

2024-02-05 02:42:28

by kernel test robot

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 3/3] bpf: treewide: Annotate BPF kfuncs in BTF

Hello,

kernel test robot noticed "WARNING:at_kernel/bpf/btf.c:#register_btf_kfunc_id_set" on:

commit: 918c4c7dda155568c619b4082fa83ca90ab578a6 ("[PATCH bpf-next v4 3/3] bpf: treewide: Annotate BPF kfuncs in BTF")
url: https://github.com/intel-lab-lkp/linux/commits/Daniel-Xu/bpf-btf-Support-flags-for-BTF_SET8-sets/20240129-092732
base: https://git.kernel.org/cgit/linux/kernel/git/bpf/bpf-next.git master
patch link: https://lore.kernel.org/all/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz/
patch subject: [PATCH bpf-next v4 3/3] bpf: treewide: Annotate BPF kfuncs in BTF

in testcase: boot

compiler: clang-17
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)

+-----------------------------------------------------------------+------------+------------+
| | 05221438c4 | 918c4c7dda |
+-----------------------------------------------------------------+------------+------------+
| WARNING:at_kernel/bpf/btf.c:#register_btf_kfunc_id_set | 0 | 7 |
| EIP:register_btf_kfunc_id_set | 0 | 7 |
| calltrace:do_softirq_own_stack | 0 | 7 |
+-----------------------------------------------------------------+------------+------------+

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-lkp/[email protected]

[ 49.044594][ T1] ------------[ cut here ]------------
[ 49.045857][ T1] WARNING: CPU: 1 PID: 1 at kernel/bpf/btf.c:8048 register_btf_kfunc_id_set (??:?)
[ 49.048024][ T1] Modules linked in:
[ 49.048925][ T1] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G W 6.8.0-rc1-00457-g918c4c7dda15 #6
[ 49.051230][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 49.053616][ T1] EIP: register_btf_kfunc_id_set (??:?)
[ 49.054969][ T1] Code: 04 01 75 0b b8 ea ff ff ff 83 3a 00 74 1c c3 b9 0d 00 00 00 83 f8 20 77 07 8b 0c 85 28 a2 71 d7 55 89 e5 e8 13 00 00 00 5d c3 <0f> 0b c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 89 e5 53 57
All code
========
0: 04 01 add $0x1,%al
2: 75 0b jne 0xf
4: b8 ea ff ff ff mov $0xffffffea,%eax
9: 83 3a 00 cmpl $0x0,(%rdx)
c: 74 1c je 0x2a
e: c3 retq
f: b9 0d 00 00 00 mov $0xd,%ecx
14: 83 f8 20 cmp $0x20,%eax
17: 77 07 ja 0x20
19: 8b 0c 85 28 a2 71 d7 mov -0x288e5dd8(,%rax,4),%ecx
20: 55 push %rbp
21: 89 e5 mov %esp,%ebp
23: e8 13 00 00 00 callq 0x3b
28: 5d pop %rbp
29: c3 retq
2a:* 0f 0b ud2 <-- trapping instruction
2c: c3 retq
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 90 nop
31: 90 nop
32: 90 nop
33: 90 nop
34: 90 nop
35: 90 nop
36: 90 nop
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 55 push %rbp
3c: 89 e5 mov %esp,%ebp
3e: 53 push %rbx
3f: 57 push %rdi

Code starting with the faulting instruction
===========================================
0: 0f 0b ud2
2: c3 retq
3: 90 nop
4: 90 nop
5: 90 nop
6: 90 nop
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 55 push %rbp
12: 89 e5 mov %esp,%ebp
14: 53 push %rbx
15: 57 push %rdi
[ 49.059550][ T1] EAX: ffffffea EBX: 00000000 ECX: d9356fb0 EDX: d7c2b154
[ 49.061229][ T1] ESI: 00000000 EDI: 0000019a EBP: c028dc48 ESP: c028dc38
[ 49.062886][ T1] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010246
[ 49.064685][ T1] CR0: 80050033 CR2: 00000000 CR3: 189ab000 CR4: 000406f0
[ 49.066358][ T1] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 49.068020][ T1] DR6: fffe0ff0 DR7: 00000400
[ 49.069132][ T1] Call Trace:
[ 49.069902][ T1] ? show_regs (??:?)
[ 49.070890][ T1] ? register_btf_kfunc_id_set (??:?)
[ 49.072187][ T1] ? __warn (??:?)
[ 49.073151][ T1] ? register_btf_kfunc_id_set (??:?)
[ 49.074480][ T1] ? register_btf_kfunc_id_set (??:?)
[ 49.075751][ T1] ? report_bug (??:?)
[ 49.076858][ T1] ? exc_overflow (??:?)
[ 49.077925][ T1] ? handle_bug (traps.c:?)
[ 49.078947][ T1] ? exc_invalid_op (??:?)
[ 49.080030][ T1] ? handle_exception (init_task.c:?)
[ 49.081174][ T1] ? get_seg_base_limit (insn-eval.c:?)
[ 49.082393][ T1] ? mutex_lock_killable_nested (??:?)
[ 49.083707][ T1] ? exc_overflow (??:?)
[ 49.084782][ T1] ? register_btf_kfunc_id_set (??:?)
[ 49.086126][ T1] ? mutex_lock_killable_nested (??:?)
[ 49.087468][ T1] ? exc_overflow (??:?)
[ 49.088520][ T1] ? register_btf_kfunc_id_set (??:?)
[ 49.089864][ T1] ? cubictcp_register (tcp_cubic.c:?)
[ 49.090991][ T1] do_one_initcall (??:?)
[ 49.092136][ T1] ? pvclock_clocksource_read_nowd (??:?)
[ 49.093607][ T1] ? __lock_acquire (lockdep.c:?)
[ 49.094756][ T1] ? kvm_sched_clock_read (kvmclock.c:?)
[ 49.095985][ T1] ? sched_clock_noinstr (??:?)
[ 49.097144][ T1] ? local_clock_noinstr (??:?)
[ 49.098393][ T1] ? __lock_acquire (lockdep.c:?)
[ 49.099575][ T1] ? sched_clock_noinstr (??:?)
[ 49.100746][ T1] ? local_clock_noinstr (??:?)
[ 49.101997][ T1] ? pvclock_clocksource_read_nowd (??:?)
[ 49.103439][ T1] ? kvm_sched_clock_read (kvmclock.c:?)
[ 49.104673][ T1] ? pvclock_clocksource_read_nowd (??:?)
[ 49.106095][ T1] ? kvm_sched_clock_read (kvmclock.c:?)
[ 49.107310][ T1] ? sched_clock_noinstr (??:?)
[ 49.109773][ T1] ? local_clock_noinstr (??:?)
[ 49.111018][ T1] ? __this_cpu_preempt_check (??:?)
[ 49.112289][ T1] ? irqtime_account_irq (??:?)
[ 49.113534][ T1] ? irqtime_account_delta (build_policy.c:?)
[ 49.114812][ T1] ? irqentry_exit (??:?)
[ 49.115860][ T1] ? __this_cpu_preempt_check (??:?)
[ 49.117126][ T1] ? lockdep_hardirqs_on (??:?)
[ 49.118370][ T1] ? sysvec_reboot (??:?)
[ 49.119450][ T1] ? trace_hardirqs_on (??:?)
[ 49.120623][ T1] ? irqentry_exit (??:?)
[ 49.121703][ T1] ? sysvec_reschedule_ipi (??:?)
[ 49.122962][ T1] ? handle_exception (init_task.c:?)
[ 49.124130][ T1] ? strlen (??:?)
[ 49.125054][ T1] ? next_arg (??:?)
[ 49.126086][ T1] ? parse_args (??:?)
[ 49.127134][ T1] ? tcp_diag_init (tcp_cubic.c:?)
[ 49.128257][ T1] do_initcall_level (main.c:?)
[ 49.129398][ T1] ? kernel_init (main.c:?)
[ 49.130474][ T1] do_initcalls (main.c:?)
[ 49.131494][ T1] do_basic_setup (main.c:?)
[ 49.132558][ T1] kernel_init_freeable (main.c:?)
[ 49.133781][ T1] ? rest_init (main.c:?)
[ 49.134848][ T1] ? rest_init (main.c:?)
[ 49.135885][ T1] kernel_init (main.c:?)
[ 49.136958][ T1] ret_from_fork (??:?)
[ 49.137979][ T1] ret_from_fork_asm (??:?)
[ 49.139078][ T1] entry_INT80_32 (init_task.c:?)
[ 49.140171][ T1] irq event stamp: 16737757
[ 49.141202][ T1] hardirqs last enabled at (16737765): console_unlock (??:?)
[ 49.143298][ T1] hardirqs last disabled at (16737774): console_unlock (??:?)
[ 49.145355][ T1] softirqs last enabled at (16737610): do_softirq_own_stack (??:?)
[ 49.147553][ T1] softirqs last disabled at (16737605): do_softirq_own_stack (??:?)
[ 49.149757][ T1] ---[ end trace 0000000000000000 ]---
[ 49.151671][ T1] NET: Registered PF_INET6 protocol family
[ 49.156896][ T1] Segment Routing with IPv6
[ 49.158068][ T1] In-situ OAM (IOAM) with IPv6
[ 49.159300][ T1] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
[ 49.162798][ T1] NET: Registered PF_PACKET protocol family
[ 49.164686][ T1] 9pnet: Installing 9P2000 support
[ 49.166257][ T1] start plist test
[ 49.168281][ T1] end plist test
[ 49.173855][ T1] IPI shorthand broadcast: enabled
[ 49.175165][ C0] ... APIC ID: 00000000 (0)
[ 49.176383][ C0] ... APIC VERSION: 00050014
[ 49.177486][ C0] 0000000000000000000000000000000000000000000000000000000000000000
[ 49.177486][ C0] 0000000000000000000000000000000000000000000000000000000008001000

The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20240204/[email protected]

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

2024-02-05 18:43:25

by Viktor Malik

[permalink] [raw]

Subject: Re: [PATCH bpf-next v4 0/3] Annotate kfuncs in .BTF_ids section

On 2/3/24 19:45, Manu Bretelle wrote:
> On Sat, Feb 03, 2024 at 03:40:24PM +0100, Jiri Olsa wrote:
>> On Fri, Feb 02, 2024 at 03:09:05PM -0800, Manu Bretelle wrote:
>>> On Sun, Jan 28, 2024 at 06:24:05PM -0700, Daniel Xu wrote:
>>>> === Description ===
>>>>
>>>> This is a bpf-treewide change that annotates all kfuncs as such inside
>>>> .BTF_ids. This annotation eventually allows us to automatically generate
>>>> kfunc prototypes from bpftool.
>>>>
>>>> We store this metadata inside a yet-unused flags field inside struct
>>>> btf_id_set8 (thanks Kumar!). pahole will be taught where to look.
>>>>
>>>> More details about the full chain of events are available in commit 3's
>>>> description.
>>>>
>>>> The accompanying pahole and bpftool changes can be viewed
>>>> here on these "frozen" branches [0][1].
>>>>
>>>> [0]: https://github.com/danobi/pahole/tree/kfunc_btf-v3-mailed
>>>> [1]: https://github.com/danobi/linux/tree/kfunc_bpftool-mailed
>>>
>>>
>>> I hit a similar issue to [0] on master
>>> 943b043aeecc ("selftests/bpf: Fix bench runner SIGSEGV")
>>> when cross-compiling on x86_64 (LE) to s390x (BE).
>>> I do have CONFIG_DEBUG_INFO_BTF enable and the issue would not trigger if
>>> I disabled CONFIG_DEBUG_INFO_BTF (and with the fix mentioned in [0]).
>>>
>>> What seems to happen is that `tools/resolve_btfids` is ran in the context of the
>>> host endianess and if I printk before the WARN_ON:
>>> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
>>> index ef380e546952..a9ed7a1a4936 100644
>>> --- a/kernel/bpf/btf.c
>>> +++ b/kernel/bpf/btf.c
>>> @@ -8128,6 +8128,7 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
>>> * WARN() for initcall registrations that do not check errors.
>>> */
>>> if (!(kset->set->flags & BTF_SET8_KFUNCS)) {
>>> + printk("Flag 0x%08X, expected 0x%08X\n", kset->set->flags, BTF_SET8_KFUNCS);
>>> WARN_ON(!kset->owner);
>>> return -EINVAL;
>>> }
>>>
>>> the boot logs would show:
>>> Flag 0x01000000, expected 0x00000001
>>>
>>> The issue did not happen prior to
>>> 6f3189f38a3e ("bpf: treewide: Annotate BPF kfuncs in BTF")
>>> has only 0 was written before.
>>>
>>> It seems [1] will be addressing cross-compilation, but it did not fix it as is
>>> by just applying on top of master, so probably some of the changes will also need
>>> to be ported to `tools/include/linux/btf_ids.h`?
>>
>> the fix in [1] is fixing flags in set8's pairs, but not the global flags
>>
>> it looks like Viktor's fix should now also swap that as well? like in the
>> change below on top of Viktor's changes (untested)
>>
>> jirka
>>
>>
>> ---
>> diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
>> index d01603ef6283..c44d57fec390 100644
>> --- a/tools/bpf/resolve_btfids/main.c
>> +++ b/tools/bpf/resolve_btfids/main.c
>> @@ -706,6 +706,8 @@ static int sets_patch(struct object *obj)
>> * correctly translate everything.
>> */
>> if (need_bswap) {
>> + set8->flags = bswap_32(set8->flags);
>> +
>> for (i = 0; i < cnt; i++) {
>> set8->pairs[i].flags =
>> bswap_32(set8->pairs[i].flags);
>>
>
> That should work. Here are a few tests I ran:
>
> $ md5sum /tmp/kbuild-s390x/vmlinux.*
> eb658e51e089f3c5b2c8909a29dc9997 /tmp/kbuild-s390x/vmlinux.a
> # plain vmlinux before running resolv_btfids (all 0s)
> ea907cd46a1a73b8276b5f2a82af00ca /tmp/kbuild-s390x/vmlinux.before_resolv
> # x86_64 resolv_btfids on master without Viktor's patch
> 980a40c3a3ff563d1c2d1ebdd5071a23 /tmp/kbuild-s390x/vmlinux.resolv_native
> # x86_64 resolv_btfids on master with Viktor's patch
> b986d19e242719ebea41c578235da662 /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor
> # x86_64 resolv_btfids on master with Viktor's patch and your suggested patch
> 4edd8752ff01129945bd442689b1927b /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor_patched
> # s390x resolv_btfids run with qemu-s390x-static
> 4edd8752ff01129945bd442689b1927b /tmp/kbuild-s390x/vmlinux.resolv_s390x
>
>
> and some hexdiff of those binaries:
>
>
> # difference between master's native build and s390x build.... has byte swapping for set8 and others
> diff -ruN <(xxd /tmp/kbuild-s390x/vmlinux.resolv_s390x) <(xxd /tmp/kbuild-s390x/vmlinux.resolv_native) > diff_s390x_native.diff
> https://gist.github.com/chantra/c3d58637a08a6f7340953dc155bb18cc
>
> # difference betwee Viktor's version and s390x build.... squinting my eyes I only see the global set8 is missing
> diff -ruN <(xxd /tmp/kbuild-s390x/vmlinux.resolv_s390x) <(xxd /tmp/kbuild-s390x/vmlinux.resolv_native_patch_viktor) > diff_s390x_native_viktor.diff
> https://gist.github.com/chantra/61cfff02b456ae72d3c0161ce1897097

Thanks for the testing Manu!

Jiri's suggested fix is now a part of [1].

Viktor

[1] https://lore.kernel.org/bpf/[email protected]/

>
> Have a good weekend all!
>
> Manu
>