This adds an opt-in interface for tracepoints to expose a writable context to
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE programs that are attached, while
supporting read-only access from existing BPF_PROG_TYPE_RAW_TRACEPOINT
programs, as well as from non-BPF-based tracepoints.
The initial motivation is to support tracing that can be observed from the
remote end of an NBD socket, e.g. by adding flags to the struct nbd_request
header. Earlier attempts included adding an NBD-specific tracepoint fd, but in
code review, I was recommended to implement it more generically -- as a result,
this patchset is far simpler than my initial try.
v1->v2:
* add selftests
* sync tools/include/uapi/linux/bpf.h
* reject variable offset into the buffer
* add string representation of PTR_TO_TP_BUFFER to reg_type_str
Andrew Hall (1):
nbd: add tracepoints for send/receive timing
Matt Mullins (4):
bpf: add writable context for raw tracepoints
nbd: trace sending nbd requests
tools: sync bpf.h
selftests: bpf: test writable buffers in raw tps
MAINTAINERS | 1 +
drivers/block/nbd.c | 13 ++
include/linux/bpf.h | 2 +
include/linux/bpf_types.h | 1 +
include/linux/tracepoint-defs.h | 1 +
include/trace/bpf_probe.h | 27 +++-
include/trace/events/bpf_test_run.h | 50 ++++++
include/trace/events/nbd.h | 148 ++++++++++++++++++
include/uapi/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 8 +-
kernel/bpf/verifier.c | 31 ++++
kernel/trace/bpf_trace.c | 21 +++
net/bpf/test_run.c | 4 +
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/libbpf.c | 1 +
tools/lib/bpf/libbpf_probes.c | 1 +
.../raw_tp_writable_reject_nbd_invalid.c | 40 +++++
.../bpf/prog_tests/raw_tp_writable_test_run.c | 80 ++++++++++
.../selftests/bpf/verifier/raw_tp_writable.c | 34 ++++
19 files changed, 461 insertions(+), 4 deletions(-)
create mode 100644 include/trace/events/bpf_test_run.h
create mode 100644 include/trace/events/nbd.h
create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c
create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c
create mode 100644 tools/testing/selftests/bpf/verifier/raw_tp_writable.c
--
2.17.1
This is an opt-in interface that allows a tracepoint to provide a safe
buffer that can be written from a BPF_PROG_TYPE_RAW_TRACEPOINT program.
The size of the buffer must be a compile-time constant, and is checked
before allowing a BPF program to attach to a tracepoint that uses this
feature.
The pointer to this buffer will be the first argument of tracepoints
that opt in; the buffer is readable by both BPF_PROG_TYPE_RAW_TRACEPOINT
and BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE programs that attach to such a
tracepoint, but the buffer to which it points may only be written by the
latter.
Signed-off-by: Matt Mullins <[email protected]>
---
include/linux/bpf.h | 2 ++
include/linux/bpf_types.h | 1 +
include/linux/tracepoint-defs.h | 1 +
include/trace/bpf_probe.h | 27 +++++++++++++++++++++++++--
include/uapi/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 8 ++++++--
kernel/bpf/verifier.c | 31 +++++++++++++++++++++++++++++++
kernel/trace/bpf_trace.c | 21 +++++++++++++++++++++
8 files changed, 88 insertions(+), 4 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a2132e09dc1c..d3c71fd67476 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -263,6 +263,7 @@ enum bpf_reg_type {
PTR_TO_SOCK_COMMON_OR_NULL, /* reg points to sock_common or NULL */
PTR_TO_TCP_SOCK, /* reg points to struct tcp_sock */
PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
+ PTR_TO_TP_BUFFER, /* reg points to a writable raw tp's buffer */
};
/* The information passed from prog-specific *_is_valid_access
@@ -352,6 +353,7 @@ struct bpf_prog_aux {
u32 used_map_cnt;
u32 max_ctx_offset;
u32 max_pkt_offset;
+ u32 max_tp_access;
u32 stack_depth;
u32 id;
u32 func_cnt; /* used by non-func prog as the number of func progs */
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 08bf2f1fe553..c766108608cb 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -25,6 +25,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe)
BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint)
BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event)
BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint)
+BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, raw_tracepoint_writable)
#endif
#ifdef CONFIG_CGROUP_BPF
BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev)
diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
index 49ba9cde7e4b..b29950a19205 100644
--- a/include/linux/tracepoint-defs.h
+++ b/include/linux/tracepoint-defs.h
@@ -45,6 +45,7 @@ struct bpf_raw_event_map {
struct tracepoint *tp;
void *bpf_func;
u32 num_args;
+ u32 writable_size;
} __aligned(32);
#endif
diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index 505dae0bed80..d6e556c0a085 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -69,8 +69,7 @@ __bpf_trace_##call(void *__data, proto) \
* to make sure that if the tracepoint handling changes, the
* bpf probe will fail to compile unless it too is updated.
*/
-#undef DEFINE_EVENT
-#define DEFINE_EVENT(template, call, proto, args) \
+#define __DEFINE_EVENT(template, call, proto, args, size) \
static inline void bpf_test_probe_##call(void) \
{ \
check_trace_callback_type_##call(__bpf_trace_##template); \
@@ -81,12 +80,36 @@ __bpf_trace_tp_map_##call = { \
.tp = &__tracepoint_##call, \
.bpf_func = (void *)__bpf_trace_##template, \
.num_args = COUNT_ARGS(args), \
+ .writable_size = size, \
};
+#define FIRST(x, ...) x
+
+#undef DEFINE_EVENT_WRITABLE
+#define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
+static inline void bpf_test_buffer_##call(void) \
+{ \
+ /* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
+ * BUILD_BUG_ON_ZERO() uses a different mechanism that is not \
+ * dead-code-eliminated. \
+ */ \
+ FIRST(proto); \
+ (void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args))); \
+} \
+__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
+
+#undef DEFINE_EVENT
+#define DEFINE_EVENT(template, call, proto, args) \
+ __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+#undef DEFINE_EVENT_WRITABLE
+#undef __DEFINE_EVENT
+#undef FIRST
+
#endif /* CONFIG_BPF_EVENTS */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 3c38ac9a92a7..c5335d53ce82 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -166,6 +166,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_LIRC_MODE2,
BPF_PROG_TYPE_SK_REUSEPORT,
BPF_PROG_TYPE_FLOW_DISSECTOR,
+ BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
};
enum bpf_attach_type {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 62f6bced3a3c..27e2f22879a4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1720,12 +1720,16 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
}
raw_tp->btp = btp;
- prog = bpf_prog_get_type(attr->raw_tracepoint.prog_fd,
- BPF_PROG_TYPE_RAW_TRACEPOINT);
+ prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
if (IS_ERR(prog)) {
err = PTR_ERR(prog);
goto out_free_tp;
}
+ if (prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT &&
+ prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE) {
+ err = -EINVAL;
+ goto out_put_prog;
+ }
err = bpf_probe_register(raw_tp->btp, prog);
if (err)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ce166a002d16..32f706e99319 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -411,6 +411,7 @@ static const char * const reg_type_str[] = {
[PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null",
[PTR_TO_TCP_SOCK] = "tcp_sock",
[PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null",
+ [PTR_TO_TP_BUFFER] = "tp_buffer",
};
static char slot_type_char[] = {
@@ -1958,6 +1959,32 @@ static int check_ctx_reg(struct bpf_verifier_env *env,
return 0;
}
+static int check_tp_buffer_access(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int regno, int off, int size)
+{
+ if (off < 0) {
+ verbose(env,
+ "R%d invalid tracepoint buffer access: off=%d, size=%d",
+ regno, off, size);
+ return -EACCES;
+ }
+ if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env,
+ "R%d invalid variable buffer offset: off=%d, var_off=%s",
+ regno, off, tn_buf);
+ return -EACCES;
+ }
+ if (off + size > env->prog->aux->max_tp_access)
+ env->prog->aux->max_tp_access = off + size;
+
+ return 0;
+}
+
+
/* truncate register to smaller size (in bytes)
* must be called with size < BPF_REG_SIZE
*/
@@ -2100,6 +2127,10 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
err = check_sock_access(env, insn_idx, regno, off, size, t);
if (!err && value_regno >= 0)
mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_TP_BUFFER) {
+ err = check_tp_buffer_access(env, reg, regno, off, size);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
} else {
verbose(env, "R%d invalid mem access '%s'\n", regno,
reg_type_str[reg->type]);
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d64c00afceb5..a2dd79dc6871 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -909,6 +909,24 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
const struct bpf_prog_ops raw_tracepoint_prog_ops = {
};
+static bool raw_tp_writable_prog_is_valid_access(int off, int size,
+ enum bpf_access_type type,
+ const struct bpf_prog *prog,
+ struct bpf_insn_access_aux *info)
+{
+ if (off == 0 && size == sizeof(u64))
+ info->reg_type = PTR_TO_TP_BUFFER;
+ return raw_tp_prog_is_valid_access(off, size, type, prog, info);
+}
+
+const struct bpf_verifier_ops raw_tracepoint_writable_verifier_ops = {
+ .get_func_proto = raw_tp_prog_func_proto,
+ .is_valid_access = raw_tp_writable_prog_is_valid_access,
+};
+
+const struct bpf_prog_ops raw_tracepoint_writable_prog_ops = {
+};
+
static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
@@ -1198,6 +1216,9 @@ static int __bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *
if (prog->aux->max_ctx_offset > btp->num_args * sizeof(u64))
return -EINVAL;
+ if (prog->aux->max_tp_access > btp->writable_size)
+ return -EINVAL;
+
return tracepoint_probe_register(tp, (void *)btp->bpf_func, prog);
}
--
2.17.1
This adds BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, and fixes up the
error: enumeration value ‘BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE’ not handled in switch [-Werror=switch-enum]
build errors it would otherwise cause in libbpf.
Signed-off-by: Matt Mullins <[email protected]>
---
tools/include/uapi/linux/bpf.h | 1 +
tools/lib/bpf/libbpf.c | 1 +
tools/lib/bpf/libbpf_probes.c | 1 +
3 files changed, 3 insertions(+)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 3c38ac9a92a7..c5335d53ce82 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -166,6 +166,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_LIRC_MODE2,
BPF_PROG_TYPE_SK_REUSEPORT,
BPF_PROG_TYPE_FLOW_DISSECTOR,
+ BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
};
enum bpf_attach_type {
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d5b830d60601..9b6ce703c057 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1681,6 +1681,7 @@ static bool bpf_prog_type__needs_kver(enum bpf_prog_type type)
case BPF_PROG_TYPE_UNSPEC:
case BPF_PROG_TYPE_TRACEPOINT:
case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
case BPF_PROG_TYPE_PERF_EVENT:
return false;
case BPF_PROG_TYPE_KPROBE:
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 8c3a1c04dcb2..26eff2f39bed 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -93,6 +93,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
case BPF_PROG_TYPE_CGROUP_DEVICE:
case BPF_PROG_TYPE_SK_MSG:
case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
case BPF_PROG_TYPE_LWT_SEG6LOCAL:
case BPF_PROG_TYPE_LIRC_MODE2:
case BPF_PROG_TYPE_SK_REUSEPORT:
--
2.17.1
This tests that:
* a BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE cannot be attached if it
uses either:
* a variable offset to the tracepoint buffer, or
* an offset beyond the size of the tracepoint buffer
* a tracer can modify the buffer provided when attached to a writable
tracepoint in bpf_prog_test_run
Signed-off-by: Matt Mullins <[email protected]>
---
include/trace/events/bpf_test_run.h | 50 ++++++++++++
net/bpf/test_run.c | 4 +
.../raw_tp_writable_reject_nbd_invalid.c | 40 ++++++++++
.../bpf/prog_tests/raw_tp_writable_test_run.c | 80 +++++++++++++++++++
.../selftests/bpf/verifier/raw_tp_writable.c | 34 ++++++++
5 files changed, 208 insertions(+)
create mode 100644 include/trace/events/bpf_test_run.h
create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c
create mode 100644 tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c
create mode 100644 tools/testing/selftests/bpf/verifier/raw_tp_writable.c
diff --git a/include/trace/events/bpf_test_run.h b/include/trace/events/bpf_test_run.h
new file mode 100644
index 000000000000..abf466839ea4
--- /dev/null
+++ b/include/trace/events/bpf_test_run.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bpf_test_run
+
+#if !defined(_TRACE_NBD_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BPF_TEST_RUN_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(bpf_test_finish,
+
+ TP_PROTO(int *err),
+
+ TP_ARGS(err),
+
+ TP_STRUCT__entry(
+ __field(int, err)
+ ),
+
+ TP_fast_assign(
+ __entry->err = *err;
+ ),
+
+ TP_printk("bpf_test_finish with err=%d", __entry->err)
+);
+
+#ifdef DEFINE_EVENT_WRITABLE
+#undef BPF_TEST_RUN_DEFINE_EVENT
+#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size) \
+ DEFINE_EVENT_WRITABLE(template, call, PARAMS(proto), \
+ PARAMS(args), size)
+#else
+#undef BPF_TEST_RUN_DEFINE_EVENT
+#define BPF_TEST_RUN_DEFINE_EVENT(template, call, proto, args, size) \
+ DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args))
+#endif
+
+BPF_TEST_RUN_DEFINE_EVENT(bpf_test_finish, bpf_test_finish,
+
+ TP_PROTO(int *err),
+
+ TP_ARGS(err),
+
+ sizeof(int)
+);
+
+#endif
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index fab142b796ef..25e757102595 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -13,6 +13,9 @@
#include <net/sock.h>
#include <net/tcp.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/bpf_test_run.h>
+
static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,
u32 *retval, u32 *time)
{
@@ -100,6 +103,7 @@ static int bpf_test_finish(const union bpf_attr *kattr,
if (err != -ENOSPC)
err = 0;
out:
+ trace_bpf_test_finish(&err);
return err;
}
diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c
new file mode 100644
index 000000000000..328d5c4b084b
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_reject_nbd_invalid.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <linux/nbd.h>
+
+void test_raw_tp_writable_reject_nbd_invalid(void)
+{
+ __u32 duration = 0;
+ char error[4096];
+ int bpf_fd = -1, tp_fd = -1;
+
+ const struct bpf_insn program[] = {
+ /* r6 is our tp buffer */
+ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_6, 128),
+ BPF_EXIT_INSN(),
+ };
+
+ struct bpf_load_program_attr load_attr = {
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ .license = "GPL v2",
+ .insns = program,
+ .insns_cnt = sizeof(program) / sizeof(struct bpf_insn),
+ .log_level = 2,
+ };
+
+ bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));
+ if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable loaded",
+ "failed: %d errno %d\n", bpf_fd, errno))
+ return;
+
+ tp_fd = bpf_raw_tracepoint_open("nbd_send_request", bpf_fd);
+ if (CHECK(tp_fd >= 0, "bpf_raw_tracepoint_writable opened",
+ "erroneously succeeded\n"))
+ goto out_bpffd;
+
+ close(tp_fd);
+out_bpffd:
+ close(bpf_fd);
+}
diff --git a/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c
new file mode 100644
index 000000000000..4145925f9cab
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/raw_tp_writable_test_run.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <linux/nbd.h>
+
+void test_raw_tp_writable_test_run(void)
+{
+ __u32 duration = 0;
+ char error[4096];
+
+ const struct bpf_insn trace_program[] = {
+ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, 0),
+ BPF_LD_IMM64(BPF_REG_0, 42),
+ BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+
+ struct bpf_load_program_attr load_attr = {
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ .license = "GPL v2",
+ .insns = trace_program,
+ .insns_cnt = sizeof(trace_program) / sizeof(struct bpf_insn),
+ .log_level = 2,
+ };
+
+ int bpf_fd = bpf_load_program_xattr(&load_attr, error, sizeof(error));
+ if (CHECK(bpf_fd < 0, "bpf_raw_tracepoint_writable loaded",
+ "failed: %d errno %d\n", bpf_fd, errno))
+ return;
+
+ const struct bpf_insn skb_program[] = {
+ BPF_LD_IMM64(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+
+ struct bpf_load_program_attr skb_load_attr = {
+ .prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+ .license = "GPL v2",
+ .insns = skb_program,
+ .insns_cnt = sizeof(skb_program) / sizeof(struct bpf_insn),
+ };
+
+ int filter_fd =
+ bpf_load_program_xattr(&skb_load_attr, error, sizeof(error));
+ if (CHECK(filter_fd < 0, "test_program_loaded", "failed: %d errno %d\n",
+ filter_fd, errno))
+ goto out_bpffd;
+
+ int tp_fd = bpf_raw_tracepoint_open("bpf_test_finish", bpf_fd);
+ if (CHECK(tp_fd < 0, "bpf_raw_tracepoint_writable opened",
+ "failed: %d errno %d\n", tp_fd, errno))
+ goto out_filterfd;
+
+ char test_skb[128] = {
+ 0,
+ };
+
+ __u32 prog_ret;
+ int err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0,
+ 0, &prog_ret, 0);
+ CHECK(err != 42, "test_run",
+ "tracepoint did not modify return value\n");
+ CHECK(prog_ret != 0, "test_run_ret",
+ "socket_filter did not return 0\n");
+
+ close(tp_fd);
+
+ err = bpf_prog_test_run(filter_fd, 1, test_skb, sizeof(test_skb), 0, 0,
+ &prog_ret, 0);
+ CHECK(err != 0, "test_run_notrace",
+ "test_run failed with %d errno %d\n", err, errno);
+ CHECK(prog_ret != 0, "test_run_ret_notrace",
+ "socket_filter did not return 0\n");
+
+out_filterfd:
+ close(filter_fd);
+out_bpffd:
+ close(bpf_fd);
+}
diff --git a/tools/testing/selftests/bpf/verifier/raw_tp_writable.c b/tools/testing/selftests/bpf/verifier/raw_tp_writable.c
new file mode 100644
index 000000000000..95b5d70a1dc1
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/raw_tp_writable.c
@@ -0,0 +1,34 @@
+{
+ "raw_tracepoint_writable: reject variable offset",
+ .insns = {
+ /* r6 is our tp buffer */
+ BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
+
+ BPF_LD_MAP_FD(BPF_REG_1, 0),
+ /* move the key (== 0) to r10-8 */
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
+ /* lookup in the map */
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_map_lookup_elem),
+
+ /* exit clean if null */
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+
+ /* shift the buffer pointer to a variable location */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0),
+ /* clobber whatever's there */
+ BPF_MOV64_IMM(BPF_REG_7, 4242),
+ BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0),
+
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .fixup_map_hash_8b = { 1, },
+ .prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ .errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)",
+},
--
2.17.1
From: Andrew Hall <[email protected]>
This adds four tracepoints to nbd, enabling separate tracing of payload
and header sending/receipt.
In the send path for headers that have already been sent, we also
explicitly initialize the handle so it can be referenced by the later
tracepoint.
Signed-off-by: Andrew Hall <[email protected]>
Signed-off-by: Matt Mullins <[email protected]>
---
drivers/block/nbd.c | 8 ++++
include/trace/events/nbd.h | 92 ++++++++++++++++++++++++++++++++++++++
2 files changed, 100 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 7393d04d255c..d3d914620f66 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -513,6 +513,10 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
if (sent) {
if (sent >= sizeof(request)) {
skip = sent - sizeof(request);
+
+ // initialize handle for tracing purposes
+ handle = nbd_cmd_handle(cmd);
+
goto send_pages;
}
iov_iter_advance(&from, sent);
@@ -536,6 +540,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
result = sock_xmit(nbd, index, 1, &from,
(type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
+ trace_nbd_header_sent(req, handle);
if (result <= 0) {
if (was_interrupted(result)) {
/* If we havne't sent anything we can just return BUSY,
@@ -608,6 +613,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
bio = next;
}
out:
+ trace_nbd_payload_sent(req, handle);
nsock->pending = NULL;
nsock->sent = 0;
return 0;
@@ -655,6 +661,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
tag, req);
return ERR_PTR(-ENOENT);
}
+ trace_nbd_header_received(req, handle);
cmd = blk_mq_rq_to_pdu(req);
mutex_lock(&cmd->lock);
@@ -708,6 +715,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
}
}
out:
+ trace_nbd_payload_received(req, handle);
mutex_unlock(&cmd->lock);
return ret ? ERR_PTR(ret) : cmd;
}
diff --git a/include/trace/events/nbd.h b/include/trace/events/nbd.h
index 5928255ed02e..eef476fef95a 100644
--- a/include/trace/events/nbd.h
+++ b/include/trace/events/nbd.h
@@ -7,6 +7,98 @@
#include <linux/tracepoint.h>
+TRACE_EVENT(nbd_header_sent,
+
+ TP_PROTO(struct request *req, u64 handle),
+
+ TP_ARGS(req, handle),
+
+ TP_STRUCT__entry(
+ __field(struct request *, req)
+ __field(u64, handle)
+ ),
+
+ TP_fast_assign(
+ __entry->req = req;
+ __entry->handle = handle;
+ ),
+
+ TP_printk(
+ "nbd header sent: request %p, handle 0x%016llx",
+ __entry->req,
+ __entry->handle
+ )
+);
+
+TRACE_EVENT(nbd_payload_sent,
+
+ TP_PROTO(struct request *req, u64 handle),
+
+ TP_ARGS(req, handle),
+
+ TP_STRUCT__entry(
+ __field(struct request *, req)
+ __field(u64, handle)
+ ),
+
+ TP_fast_assign(
+ __entry->req = req;
+ __entry->handle = handle;
+ ),
+
+ TP_printk(
+ "nbd payload sent: request %p, handle 0x%016llx",
+ __entry->req,
+ __entry->handle
+ )
+);
+
+TRACE_EVENT(nbd_header_received,
+
+ TP_PROTO(struct request *req, u64 handle),
+
+ TP_ARGS(req, handle),
+
+ TP_STRUCT__entry(
+ __field(struct request *, req)
+ __field(u64, handle)
+ ),
+
+ TP_fast_assign(
+ __entry->req = req;
+ __entry->handle = handle;
+ ),
+
+ TP_printk(
+ "nbd header received: request %p, handle 0x%016llx",
+ __entry->req,
+ __entry->handle
+ )
+);
+
+TRACE_EVENT(nbd_payload_received,
+
+ TP_PROTO(struct request *req, u64 handle),
+
+ TP_ARGS(req, handle),
+
+ TP_STRUCT__entry(
+ __field(struct request *, req)
+ __field(u64, handle)
+ ),
+
+ TP_fast_assign(
+ __entry->req = req;
+ __entry->handle = handle;
+ ),
+
+ TP_printk(
+ "nbd payload received: request %p, handle 0x%016llx",
+ __entry->req,
+ __entry->handle
+ )
+);
+
DECLARE_EVENT_CLASS(nbd_send_request,
TP_PROTO(struct nbd_request *nbd_request, int index,
--
2.17.1
This adds a tracepoint that can both observe the nbd request being sent
to the server, as well as modify that request , e.g., setting a flag in
the request that will cause the server to collect detailed tracing data.
The struct request * being handled is included to permit correlation
with the block tracepoints.
Signed-off-by: Matt Mullins <[email protected]>
---
MAINTAINERS | 1 +
drivers/block/nbd.c | 5 ++++
include/trace/events/nbd.h | 56 ++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+)
create mode 100644 include/trace/events/nbd.h
diff --git a/MAINTAINERS b/MAINTAINERS
index e17ebf70b548..6db583d2b0ea 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10737,6 +10737,7 @@ L: [email protected]
L: [email protected]
F: Documentation/blockdev/nbd.txt
F: drivers/block/nbd.c
+F: include/trace/events/nbd.h
F: include/uapi/linux/nbd.h
NETWORK DROP MONITOR
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 90ba9f4c03f3..7393d04d255c 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -44,6 +44,9 @@
#include <linux/nbd-netlink.h>
#include <net/genetlink.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/nbd.h>
+
static DEFINE_IDR(nbd_index_idr);
static DEFINE_MUTEX(nbd_index_mutex);
static int nbd_total_devices = 0;
@@ -526,6 +529,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
handle = nbd_cmd_handle(cmd);
memcpy(request.handle, &handle, sizeof(handle));
+ trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
+
dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
req, nbdcmd_to_ascii(type),
(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
diff --git a/include/trace/events/nbd.h b/include/trace/events/nbd.h
new file mode 100644
index 000000000000..5928255ed02e
--- /dev/null
+++ b/include/trace/events/nbd.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM nbd
+
+#if !defined(_TRACE_NBD_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_NBD_H
+
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(nbd_send_request,
+
+ TP_PROTO(struct nbd_request *nbd_request, int index,
+ struct request *rq),
+
+ TP_ARGS(nbd_request, index, rq),
+
+ TP_STRUCT__entry(
+ __field(struct nbd_request *, nbd_request)
+ __field(u64, dev_index)
+ __field(struct request *, request)
+ ),
+
+ TP_fast_assign(
+ __entry->nbd_request = 0;
+ __entry->dev_index = index;
+ __entry->request = rq;
+ ),
+
+ TP_printk("nbd%lld: request %p", __entry->dev_index, __entry->request)
+);
+
+#ifdef DEFINE_EVENT_WRITABLE
+#undef NBD_DEFINE_EVENT
+#define NBD_DEFINE_EVENT(template, call, proto, args, size) \
+ DEFINE_EVENT_WRITABLE(template, call, PARAMS(proto), \
+ PARAMS(args), size)
+#else
+#undef NBD_DEFINE_EVENT
+#define NBD_DEFINE_EVENT(template, call, proto, args, size) \
+ DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args))
+#endif
+
+NBD_DEFINE_EVENT(nbd_send_request, nbd_send_request,
+
+ TP_PROTO(struct nbd_request *nbd_request, int index,
+ struct request *rq),
+
+ TP_ARGS(nbd_request, index, rq),
+
+ sizeof(struct nbd_request)
+);
+
+#endif
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
2.17.1
On Fri, Apr 05, 2019 at 04:55:03PM -0700, Matt Mullins wrote:
> This adds a tracepoint that can both observe the nbd request being sent
> to the server, as well as modify that request , e.g., setting a flag in
> the request that will cause the server to collect detailed tracing data.
>
> The struct request * being handled is included to permit correlation
> with the block tracepoints.
>
> Signed-off-by: Matt Mullins <[email protected]>
> ---
> MAINTAINERS | 1 +
> drivers/block/nbd.c | 5 ++++
> include/trace/events/nbd.h | 56 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 62 insertions(+)
> create mode 100644 include/trace/events/nbd.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e17ebf70b548..6db583d2b0ea 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10737,6 +10737,7 @@ L: [email protected]
> L: [email protected]
> F: Documentation/blockdev/nbd.txt
> F: drivers/block/nbd.c
> +F: include/trace/events/nbd.h
> F: include/uapi/linux/nbd.h
>
> NETWORK DROP MONITOR
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 90ba9f4c03f3..7393d04d255c 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -44,6 +44,9 @@
> #include <linux/nbd-netlink.h>
> #include <net/genetlink.h>
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/nbd.h>
> +
> static DEFINE_IDR(nbd_index_idr);
> static DEFINE_MUTEX(nbd_index_mutex);
> static int nbd_total_devices = 0;
> @@ -526,6 +529,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
> handle = nbd_cmd_handle(cmd);
> memcpy(request.handle, &handle, sizeof(handle));
>
> + trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
> +
Just use the handle, not the pointer. Thanks,
Josef
On Fri, Apr 05, 2019 at 04:55:04PM -0700, Matt Mullins wrote:
> From: Andrew Hall <[email protected]>
>
> This adds four tracepoints to nbd, enabling separate tracing of payload
> and header sending/receipt.
>
> In the send path for headers that have already been sent, we also
> explicitly initialize the handle so it can be referenced by the later
> tracepoint.
>
> Signed-off-by: Andrew Hall <[email protected]>
> Signed-off-by: Matt Mullins <[email protected]>
> ---
> drivers/block/nbd.c | 8 ++++
> include/trace/events/nbd.h | 92 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 100 insertions(+)
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 7393d04d255c..d3d914620f66 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -513,6 +513,10 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
> if (sent) {
> if (sent >= sizeof(request)) {
> skip = sent - sizeof(request);
> +
> + // initialize handle for tracing purposes
> + handle = nbd_cmd_handle(cmd);
> +
Don't use c++ style commenting.
> goto send_pages;
> }
> iov_iter_advance(&from, sent);
> @@ -536,6 +540,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
> (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
> result = sock_xmit(nbd, index, 1, &from,
> (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
> + trace_nbd_header_sent(req, handle);
> if (result <= 0) {
> if (was_interrupted(result)) {
> /* If we havne't sent anything we can just return BUSY,
> @@ -608,6 +613,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
> bio = next;
> }
> out:
> + trace_nbd_payload_sent(req, handle);
> nsock->pending = NULL;
> nsock->sent = 0;
> return 0;
> @@ -655,6 +661,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
> tag, req);
> return ERR_PTR(-ENOENT);
> }
> + trace_nbd_header_received(req, handle);
> cmd = blk_mq_rq_to_pdu(req);
>
> mutex_lock(&cmd->lock);
> @@ -708,6 +715,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
> }
> }
> out:
> + trace_nbd_payload_received(req, handle);
> mutex_unlock(&cmd->lock);
> return ret ? ERR_PTR(ret) : cmd;
> }
> diff --git a/include/trace/events/nbd.h b/include/trace/events/nbd.h
> index 5928255ed02e..eef476fef95a 100644
> --- a/include/trace/events/nbd.h
> +++ b/include/trace/events/nbd.h
> @@ -7,6 +7,98 @@
>
> #include <linux/tracepoint.h>
>
> +TRACE_EVENT(nbd_header_sent,
> +
> + TP_PROTO(struct request *req, u64 handle),
> +
> + TP_ARGS(req, handle),
> +
> + TP_STRUCT__entry(
> + __field(struct request *, req)
> + __field(u64, handle)
> + ),
> +
> + TP_fast_assign(
> + __entry->req = req;
> + __entry->handle = handle;
> + ),
> +
> + TP_printk(
> + "nbd header sent: request %p, handle 0x%016llx",
> + __entry->req,
> + __entry->handle
> + )
> +);
> +
These are all the same, use DECLARE_EVENT_CLASS() and then just DEFINE_EVENT()
for each individual event. Also no pointers, we don't want to leak pointers to
userspace for stuff. Thanks,
Josef
On Sat, 2019-04-06 at 20:10 -0400, Josef Bacik wrote:
> On Fri, Apr 05, 2019 at 04:55:03PM -0700, Matt Mullins wrote:
> > This adds a tracepoint that can both observe the nbd request being sent
> > to the server, as well as modify that request , e.g., setting a flag in
> > the request that will cause the server to collect detailed tracing data.
> >
> > The struct request * being handled is included to permit correlation
> > with the block tracepoints.
> >
> > Signed-off-by: Matt Mullins <[email protected]>
> > ---
> > MAINTAINERS | 1 +
> > drivers/block/nbd.c | 5 ++++
> > include/trace/events/nbd.h | 56 ++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 62 insertions(+)
> > create mode 100644 include/trace/events/nbd.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index e17ebf70b548..6db583d2b0ea 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -10737,6 +10737,7 @@ L: [email protected]
> > L: [email protected]
> > F: Documentation/blockdev/nbd.txt
> > F: drivers/block/nbd.c
> > +F: include/trace/events/nbd.h
> > F: include/uapi/linux/nbd.h
> >
> > NETWORK DROP MONITOR
> > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > index 90ba9f4c03f3..7393d04d255c 100644
> > --- a/drivers/block/nbd.c
> > +++ b/drivers/block/nbd.c
> > @@ -44,6 +44,9 @@
> > #include <linux/nbd-netlink.h>
> > #include <net/genetlink.h>
> >
> > +#define CREATE_TRACE_POINTS
> > +#include <trace/events/nbd.h>
> > +
> > static DEFINE_IDR(nbd_index_idr);
> > static DEFINE_MUTEX(nbd_index_mutex);
> > static int nbd_total_devices = 0;
> > @@ -526,6 +529,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
> > handle = nbd_cmd_handle(cmd);
> > memcpy(request.handle, &handle, sizeof(handle));
> >
> > + trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
> > +
>
> Just use the handle, not the pointer. Thanks,
Assuming you're talking about the struct request *, we are tracing
things through from blk_mq_start_request, which emits tracepoints like
DEFINE_EVENT(block_rq, block_rq_issue,
TP_PROTO(struct request_queue *q, struct request *rq),
We need at least one of the tracepoints to observe a correlation
between NBD handle (in this case, embedded in the struct nbd_request)
and the struct request. That said, I don't actually mind if they're
the hashed kind of pointers, as long as the rest of the block
tracepoints do the same...