2023-12-07 01:47:26

by Ian Rogers

[permalink] [raw]
Subject: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
and perf_env__find_btf prefixed with __ to indicate the
env->bpf_progs.lock is assumed held. Call these variants when the lock
is held to avoid recursively taking it and potentially having a thread
deadlock with itself.

Signed-off-by: Ian Rogers <[email protected]>
---
Previously this patch was part of a larger set:
https://lore.kernel.org/lkml/[email protected]/
---
tools/perf/util/bpf-event.c | 8 +++---
tools/perf/util/bpf-event.h | 12 ++++-----
tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
tools/perf/util/env.h | 4 +++
tools/perf/util/header.c | 8 +++---
5 files changed, 51 insertions(+), 34 deletions(-)

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 830711cae30d..3573e0b7ef3e 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
}

-void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
- struct perf_env *env,
- FILE *fp)
+void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
+ struct perf_env *env,
+ FILE *fp)
{
__u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
__u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
@@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
if (info->btf_id) {
struct btf_node *node;

- node = perf_env__find_btf(env, info->btf_id);
+ node = __perf_env__find_btf(env, info->btf_id);
if (node)
btf = btf__new((__u8 *)(node->data),
node->data_size);
diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
index 1bcbd4fb6c66..e2f0420905f5 100644
--- a/tools/perf/util/bpf-event.h
+++ b/tools/perf/util/bpf-event.h
@@ -33,9 +33,9 @@ struct btf_node {
int machine__process_bpf(struct machine *machine, union perf_event *event,
struct perf_sample *sample);
int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
-void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
- struct perf_env *env,
- FILE *fp);
+void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
+ struct perf_env *env,
+ FILE *fp);
#else
static inline int machine__process_bpf(struct machine *machine __maybe_unused,
union perf_event *event __maybe_unused,
@@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
return 0;
}

-static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
- struct perf_env *env __maybe_unused,
- FILE *fp __maybe_unused)
+static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
+ struct perf_env *env __maybe_unused,
+ FILE *fp __maybe_unused)
{

}
diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index c68b7a004f29..cfdacbf29456 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -22,15 +22,20 @@ struct perf_env perf_env;
#include "bpf-utils.h"
#include <bpf/libbpf.h>

-void perf_env__insert_bpf_prog_info(struct perf_env *env,
- struct bpf_prog_info_node *info_node)
+void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
+{
+ down_write(&env->bpf_progs.lock);
+ __perf_env__insert_bpf_prog_info(env, info_node);
+ up_write(&env->bpf_progs.lock);
+}
+
+void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
{
__u32 prog_id = info_node->info_linear->info.id;
struct bpf_prog_info_node *node;
struct rb_node *parent = NULL;
struct rb_node **p;

- down_write(&env->bpf_progs.lock);
p = &env->bpf_progs.infos.rb_node;

while (*p != NULL) {
@@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
p = &(*p)->rb_right;
} else {
pr_debug("duplicated bpf prog info %u\n", prog_id);
- goto out;
+ return;
}
}

rb_link_node(&info_node->rb_node, parent, p);
rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
env->bpf_progs.infos_cnt++;
-out:
- up_write(&env->bpf_progs.lock);
}

struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
@@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
}

bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
+{
+ bool ret;
+
+ down_write(&env->bpf_progs.lock);
+ ret = __perf_env__insert_btf(env, btf_node);
+ up_write(&env->bpf_progs.lock);
+ return ret;
+}
+
+bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
{
struct rb_node *parent = NULL;
__u32 btf_id = btf_node->id;
struct btf_node *node;
struct rb_node **p;
- bool ret = true;

- down_write(&env->bpf_progs.lock);
p = &env->bpf_progs.btfs.rb_node;

while (*p != NULL) {
@@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
p = &(*p)->rb_right;
} else {
pr_debug("duplicated btf %u\n", btf_id);
- ret = false;
- goto out;
+ return false;
}
}

rb_link_node(&btf_node->rb_node, parent, p);
rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
env->bpf_progs.btfs_cnt++;
-out:
- up_write(&env->bpf_progs.lock);
- return ret;
+ return true;
}

struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
+{
+ struct btf_node *res;
+
+ down_read(&env->bpf_progs.lock);
+ res = __perf_env__find_btf(env, btf_id);
+ up_read(&env->bpf_progs.lock);
+ return res;
+}
+
+struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
{
struct btf_node *node = NULL;
struct rb_node *n;

- down_read(&env->bpf_progs.lock);
n = env->bpf_progs.btfs.rb_node;

while (n) {
@@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
else if (btf_id > node->id)
n = n->rb_right;
else
- goto out;
+ return node;
}
- node = NULL;
-
-out:
- up_read(&env->bpf_progs.lock);
- return node;
+ return NULL;
}

/* purge data in bpf_progs.infos tree */
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index bf7e3c4c211f..7c527e65c186 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
int perf_env__nr_cpus_avail(struct perf_env *env);

void perf_env__init(struct perf_env *env);
+void __perf_env__insert_bpf_prog_info(struct perf_env *env,
+ struct bpf_prog_info_node *info_node);
void perf_env__insert_bpf_prog_info(struct perf_env *env,
struct bpf_prog_info_node *info_node);
struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
__u32 prog_id);
bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
+bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
+struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);

int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 08cc2febabde..02bf9d8b5f74 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
node = rb_entry(next, struct bpf_prog_info_node, rb_node);
next = rb_next(&node->rb_node);

- bpf_event__print_bpf_prog_info(&node->info_linear->info,
- env, fp);
+ __bpf_event__print_bpf_prog_info(&node->info_linear->info,
+ env, fp);
}

up_read(&env->bpf_progs.lock);
@@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
/* after reading from file, translate offset to address */
bpil_offs_to_addr(info_linear);
info_node->info_linear = info_linear;
- perf_env__insert_bpf_prog_info(env, info_node);
+ __perf_env__insert_bpf_prog_info(env, info_node);
}

up_write(&env->bpf_progs.lock);
@@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
if (__do_read(ff, node->data, data_size))
goto out;

- perf_env__insert_btf(env, node);
+ __perf_env__insert_btf(env, node);
node = NULL;
}

--
2.43.0.rc2.451.g8631bc7472-goog


2024-01-03 03:01:24

by Ian Rogers

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

On Wed, Dec 6, 2023 at 5:46 PM Ian Rogers <[email protected]> wrote:
>
> Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> and perf_env__find_btf prefixed with __ to indicate the
> env->bpf_progs.lock is assumed held. Call these variants when the lock
> is held to avoid recursively taking it and potentially having a thread
> deadlock with itself.
>
> Signed-off-by: Ian Rogers <[email protected]>

Ping.

Thanks,
Ian

> ---
> Previously this patch was part of a larger set:
> https://lore.kernel.org/lkml/[email protected]/
> ---
> tools/perf/util/bpf-event.c | 8 +++---
> tools/perf/util/bpf-event.h | 12 ++++-----
> tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
> tools/perf/util/env.h | 4 +++
> tools/perf/util/header.c | 8 +++---
> 5 files changed, 51 insertions(+), 34 deletions(-)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 830711cae30d..3573e0b7ef3e 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
> return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
> }
>
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp)
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp)
> {
> __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
> __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
> @@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> if (info->btf_id) {
> struct btf_node *node;
>
> - node = perf_env__find_btf(env, info->btf_id);
> + node = __perf_env__find_btf(env, info->btf_id);
> if (node)
> btf = btf__new((__u8 *)(node->data),
> node->data_size);
> diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> index 1bcbd4fb6c66..e2f0420905f5 100644
> --- a/tools/perf/util/bpf-event.h
> +++ b/tools/perf/util/bpf-event.h
> @@ -33,9 +33,9 @@ struct btf_node {
> int machine__process_bpf(struct machine *machine, union perf_event *event,
> struct perf_sample *sample);
> int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp);
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp);
> #else
> static inline int machine__process_bpf(struct machine *machine __maybe_unused,
> union perf_event *event __maybe_unused,
> @@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
> return 0;
> }
>
> -static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> - struct perf_env *env __maybe_unused,
> - FILE *fp __maybe_unused)
> +static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> + struct perf_env *env __maybe_unused,
> + FILE *fp __maybe_unused)
> {
>
> }
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index c68b7a004f29..cfdacbf29456 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -22,15 +22,20 @@ struct perf_env perf_env;
> #include "bpf-utils.h"
> #include <bpf/libbpf.h>
>
> -void perf_env__insert_bpf_prog_info(struct perf_env *env,
> - struct bpf_prog_info_node *info_node)
> +void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> +{
> + down_write(&env->bpf_progs.lock);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> + up_write(&env->bpf_progs.lock);
> +}
> +
> +void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> {
> __u32 prog_id = info_node->info_linear->info.id;
> struct bpf_prog_info_node *node;
> struct rb_node *parent = NULL;
> struct rb_node **p;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.infos.rb_node;
>
> while (*p != NULL) {
> @@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated bpf prog info %u\n", prog_id);
> - goto out;
> + return;
> }
> }
>
> rb_link_node(&info_node->rb_node, parent, p);
> rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
> env->bpf_progs.infos_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> }
>
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> @@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> }
>
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> +{
> + bool ret;
> +
> + down_write(&env->bpf_progs.lock);
> + ret = __perf_env__insert_btf(env, btf_node);
> + up_write(&env->bpf_progs.lock);
> + return ret;
> +}
> +
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> {
> struct rb_node *parent = NULL;
> __u32 btf_id = btf_node->id;
> struct btf_node *node;
> struct rb_node **p;
> - bool ret = true;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.btfs.rb_node;
>
> while (*p != NULL) {
> @@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated btf %u\n", btf_id);
> - ret = false;
> - goto out;
> + return false;
> }
> }
>
> rb_link_node(&btf_node->rb_node, parent, p);
> rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
> env->bpf_progs.btfs_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> - return ret;
> + return true;
> }
>
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> +{
> + struct btf_node *res;
> +
> + down_read(&env->bpf_progs.lock);
> + res = __perf_env__find_btf(env, btf_id);
> + up_read(&env->bpf_progs.lock);
> + return res;
> +}
> +
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> {
> struct btf_node *node = NULL;
> struct rb_node *n;
>
> - down_read(&env->bpf_progs.lock);
> n = env->bpf_progs.btfs.rb_node;
>
> while (n) {
> @@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> else if (btf_id > node->id)
> n = n->rb_right;
> else
> - goto out;
> + return node;
> }
> - node = NULL;
> -
> -out:
> - up_read(&env->bpf_progs.lock);
> - return node;
> + return NULL;
> }
>
> /* purge data in bpf_progs.infos tree */
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index bf7e3c4c211f..7c527e65c186 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
> int perf_env__nr_cpus_avail(struct perf_env *env);
>
> void perf_env__init(struct perf_env *env);
> +void __perf_env__insert_bpf_prog_info(struct perf_env *env,
> + struct bpf_prog_info_node *info_node);
> void perf_env__insert_bpf_prog_info(struct perf_env *env,
> struct bpf_prog_info_node *info_node);
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> __u32 prog_id);
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);
>
> int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
> char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 08cc2febabde..02bf9d8b5f74 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
> node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> next = rb_next(&node->rb_node);
>
> - bpf_event__print_bpf_prog_info(&node->info_linear->info,
> - env, fp);
> + __bpf_event__print_bpf_prog_info(&node->info_linear->info,
> + env, fp);
> }
>
> up_read(&env->bpf_progs.lock);
> @@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
> /* after reading from file, translate offset to address */
> bpil_offs_to_addr(info_linear);
> info_node->info_linear = info_linear;
> - perf_env__insert_bpf_prog_info(env, info_node);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> }
>
> up_write(&env->bpf_progs.lock);
> @@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
> if (__do_read(ff, node->data, data_size))
> goto out;
>
> - perf_env__insert_btf(env, node);
> + __perf_env__insert_btf(env, node);
> node = NULL;
> }
>
> --
> 2.43.0.rc2.451.g8631bc7472-goog
>

2024-01-03 09:26:15

by Jiri Olsa

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

On Wed, Dec 06, 2023 at 05:46:55PM -0800, Ian Rogers wrote:
> Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> and perf_env__find_btf prefixed with __ to indicate the
> env->bpf_progs.lock is assumed held. Call these variants when the lock
> is held to avoid recursively taking it and potentially having a thread
> deadlock with itself.
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---
> Previously this patch was part of a larger set:
> https://lore.kernel.org/lkml/[email protected]/
> ---
> tools/perf/util/bpf-event.c | 8 +++---
> tools/perf/util/bpf-event.h | 12 ++++-----
> tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
> tools/perf/util/env.h | 4 +++
> tools/perf/util/header.c | 8 +++---
> 5 files changed, 51 insertions(+), 34 deletions(-)
>

lgtm

Acked-by: Jiri Olsa <[email protected]>

jirka

> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 830711cae30d..3573e0b7ef3e 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
> return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
> }
>
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp)
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp)
> {
> __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
> __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
> @@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> if (info->btf_id) {
> struct btf_node *node;
>
> - node = perf_env__find_btf(env, info->btf_id);
> + node = __perf_env__find_btf(env, info->btf_id);
> if (node)
> btf = btf__new((__u8 *)(node->data),
> node->data_size);
> diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> index 1bcbd4fb6c66..e2f0420905f5 100644
> --- a/tools/perf/util/bpf-event.h
> +++ b/tools/perf/util/bpf-event.h
> @@ -33,9 +33,9 @@ struct btf_node {
> int machine__process_bpf(struct machine *machine, union perf_event *event,
> struct perf_sample *sample);
> int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp);
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp);
> #else
> static inline int machine__process_bpf(struct machine *machine __maybe_unused,
> union perf_event *event __maybe_unused,
> @@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
> return 0;
> }
>
> -static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> - struct perf_env *env __maybe_unused,
> - FILE *fp __maybe_unused)
> +static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> + struct perf_env *env __maybe_unused,
> + FILE *fp __maybe_unused)
> {
>
> }
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index c68b7a004f29..cfdacbf29456 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -22,15 +22,20 @@ struct perf_env perf_env;
> #include "bpf-utils.h"
> #include <bpf/libbpf.h>
>
> -void perf_env__insert_bpf_prog_info(struct perf_env *env,
> - struct bpf_prog_info_node *info_node)
> +void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> +{
> + down_write(&env->bpf_progs.lock);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> + up_write(&env->bpf_progs.lock);
> +}
> +
> +void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> {
> __u32 prog_id = info_node->info_linear->info.id;
> struct bpf_prog_info_node *node;
> struct rb_node *parent = NULL;
> struct rb_node **p;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.infos.rb_node;
>
> while (*p != NULL) {
> @@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated bpf prog info %u\n", prog_id);
> - goto out;
> + return;
> }
> }
>
> rb_link_node(&info_node->rb_node, parent, p);
> rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
> env->bpf_progs.infos_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> }
>
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> @@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> }
>
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> +{
> + bool ret;
> +
> + down_write(&env->bpf_progs.lock);
> + ret = __perf_env__insert_btf(env, btf_node);
> + up_write(&env->bpf_progs.lock);
> + return ret;
> +}
> +
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> {
> struct rb_node *parent = NULL;
> __u32 btf_id = btf_node->id;
> struct btf_node *node;
> struct rb_node **p;
> - bool ret = true;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.btfs.rb_node;
>
> while (*p != NULL) {
> @@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated btf %u\n", btf_id);
> - ret = false;
> - goto out;
> + return false;
> }
> }
>
> rb_link_node(&btf_node->rb_node, parent, p);
> rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
> env->bpf_progs.btfs_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> - return ret;
> + return true;
> }
>
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> +{
> + struct btf_node *res;
> +
> + down_read(&env->bpf_progs.lock);
> + res = __perf_env__find_btf(env, btf_id);
> + up_read(&env->bpf_progs.lock);
> + return res;
> +}
> +
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> {
> struct btf_node *node = NULL;
> struct rb_node *n;
>
> - down_read(&env->bpf_progs.lock);
> n = env->bpf_progs.btfs.rb_node;
>
> while (n) {
> @@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> else if (btf_id > node->id)
> n = n->rb_right;
> else
> - goto out;
> + return node;
> }
> - node = NULL;
> -
> -out:
> - up_read(&env->bpf_progs.lock);
> - return node;
> + return NULL;
> }
>
> /* purge data in bpf_progs.infos tree */
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index bf7e3c4c211f..7c527e65c186 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
> int perf_env__nr_cpus_avail(struct perf_env *env);
>
> void perf_env__init(struct perf_env *env);
> +void __perf_env__insert_bpf_prog_info(struct perf_env *env,
> + struct bpf_prog_info_node *info_node);
> void perf_env__insert_bpf_prog_info(struct perf_env *env,
> struct bpf_prog_info_node *info_node);
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> __u32 prog_id);
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);
>
> int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
> char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 08cc2febabde..02bf9d8b5f74 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
> node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> next = rb_next(&node->rb_node);
>
> - bpf_event__print_bpf_prog_info(&node->info_linear->info,
> - env, fp);
> + __bpf_event__print_bpf_prog_info(&node->info_linear->info,
> + env, fp);
> }
>
> up_read(&env->bpf_progs.lock);
> @@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
> /* after reading from file, translate offset to address */
> bpil_offs_to_addr(info_linear);
> info_node->info_linear = info_linear;
> - perf_env__insert_bpf_prog_info(env, info_node);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> }
>
> up_write(&env->bpf_progs.lock);
> @@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
> if (__do_read(ff, node->data, data_size))
> goto out;
>
> - perf_env__insert_btf(env, node);
> + __perf_env__insert_btf(env, node);
> node = NULL;
> }
>
> --
> 2.43.0.rc2.451.g8631bc7472-goog
>

2024-01-03 16:09:28

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

Em Wed, Dec 06, 2023 at 05:46:55PM -0800, Ian Rogers escreveu:
> Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> and perf_env__find_btf prefixed with __ to indicate the
> env->bpf_progs.lock is assumed held. Call these variants when the lock
> is held to avoid recursively taking it and potentially having a thread
> deadlock with itself.
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---
> Previously this patch was part of a larger set:
> https://lore.kernel.org/lkml/[email protected]/
> ---
> tools/perf/util/bpf-event.c | 8 +++---
> tools/perf/util/bpf-event.h | 12 ++++-----
> tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
> tools/perf/util/env.h | 4 +++
> tools/perf/util/header.c | 8 +++---
> 5 files changed, 51 insertions(+), 34 deletions(-)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 830711cae30d..3573e0b7ef3e 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
> return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
> }
>
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp)
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp)
> {
> __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
> __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
> @@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> if (info->btf_id) {
> struct btf_node *node;
>
> - node = perf_env__find_btf(env, info->btf_id);
> + node = __perf_env__find_btf(env, info->btf_id);
> if (node)
> btf = btf__new((__u8 *)(node->data),
> node->data_size);
> diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> index 1bcbd4fb6c66..e2f0420905f5 100644
> --- a/tools/perf/util/bpf-event.h
> +++ b/tools/perf/util/bpf-event.h
> @@ -33,9 +33,9 @@ struct btf_node {
> int machine__process_bpf(struct machine *machine, union perf_event *event,
> struct perf_sample *sample);
> int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
> -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> - struct perf_env *env,
> - FILE *fp);
> +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> + struct perf_env *env,
> + FILE *fp);
> #else
> static inline int machine__process_bpf(struct machine *machine __maybe_unused,
> union perf_event *event __maybe_unused,
> @@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
> return 0;
> }
>
> -static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> - struct perf_env *env __maybe_unused,
> - FILE *fp __maybe_unused)
> +static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> + struct perf_env *env __maybe_unused,
> + FILE *fp __maybe_unused)
> {
>
> }
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index c68b7a004f29..cfdacbf29456 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -22,15 +22,20 @@ struct perf_env perf_env;
> #include "bpf-utils.h"
> #include <bpf/libbpf.h>
>
> -void perf_env__insert_bpf_prog_info(struct perf_env *env,
> - struct bpf_prog_info_node *info_node)
> +void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> +{
> + down_write(&env->bpf_progs.lock);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> + up_write(&env->bpf_progs.lock);
> +}

Minor nit/modification:

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index cfdacbf294566c33..a459374d0a1a1dc8 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -22,7 +22,8 @@ struct perf_env perf_env;
#include "bpf-utils.h"
#include <bpf/libbpf.h>

-void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
+void perf_env__insert_bpf_prog_info(struct perf_env *env,
+ struct bpf_prog_info_node *info_node)
{
down_write(&env->bpf_progs.lock);
__perf_env__insert_bpf_prog_info(env, info_node);

Just to reduce patch size a bit, just like happened with
perf_env__insert_btf() further down, where its body was changed to call
the __ variant but the non __ function got just the body modified.

- Arnaldo

> +void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> {
> __u32 prog_id = info_node->info_linear->info.id;
> struct bpf_prog_info_node *node;
> struct rb_node *parent = NULL;
> struct rb_node **p;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.infos.rb_node;
>
> while (*p != NULL) {
> @@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated bpf prog info %u\n", prog_id);
> - goto out;
> + return;
> }
> }
>
> rb_link_node(&info_node->rb_node, parent, p);
> rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
> env->bpf_progs.infos_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> }
>
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> @@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> }
>
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> +{
> + bool ret;
> +
> + down_write(&env->bpf_progs.lock);
> + ret = __perf_env__insert_btf(env, btf_node);
> + up_write(&env->bpf_progs.lock);
> + return ret;
> +}
> +
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> {
> struct rb_node *parent = NULL;
> __u32 btf_id = btf_node->id;
> struct btf_node *node;
> struct rb_node **p;
> - bool ret = true;
>
> - down_write(&env->bpf_progs.lock);
> p = &env->bpf_progs.btfs.rb_node;
>
> while (*p != NULL) {
> @@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> p = &(*p)->rb_right;
> } else {
> pr_debug("duplicated btf %u\n", btf_id);
> - ret = false;
> - goto out;
> + return false;
> }
> }
>
> rb_link_node(&btf_node->rb_node, parent, p);
> rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
> env->bpf_progs.btfs_cnt++;
> -out:
> - up_write(&env->bpf_progs.lock);
> - return ret;
> + return true;
> }
>
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> +{
> + struct btf_node *res;
> +
> + down_read(&env->bpf_progs.lock);
> + res = __perf_env__find_btf(env, btf_id);
> + up_read(&env->bpf_progs.lock);
> + return res;
> +}
> +
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> {
> struct btf_node *node = NULL;
> struct rb_node *n;
>
> - down_read(&env->bpf_progs.lock);
> n = env->bpf_progs.btfs.rb_node;
>
> while (n) {
> @@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> else if (btf_id > node->id)
> n = n->rb_right;
> else
> - goto out;
> + return node;
> }
> - node = NULL;
> -
> -out:
> - up_read(&env->bpf_progs.lock);
> - return node;
> + return NULL;
> }
>
> /* purge data in bpf_progs.infos tree */
> diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> index bf7e3c4c211f..7c527e65c186 100644
> --- a/tools/perf/util/env.h
> +++ b/tools/perf/util/env.h
> @@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
> int perf_env__nr_cpus_avail(struct perf_env *env);
>
> void perf_env__init(struct perf_env *env);
> +void __perf_env__insert_bpf_prog_info(struct perf_env *env,
> + struct bpf_prog_info_node *info_node);
> void perf_env__insert_bpf_prog_info(struct perf_env *env,
> struct bpf_prog_info_node *info_node);
> struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> __u32 prog_id);
> bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);
>
> int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
> char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 08cc2febabde..02bf9d8b5f74 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
> node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> next = rb_next(&node->rb_node);
>
> - bpf_event__print_bpf_prog_info(&node->info_linear->info,
> - env, fp);
> + __bpf_event__print_bpf_prog_info(&node->info_linear->info,
> + env, fp);
> }
>
> up_read(&env->bpf_progs.lock);
> @@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
> /* after reading from file, translate offset to address */
> bpil_offs_to_addr(info_linear);
> info_node->info_linear = info_linear;
> - perf_env__insert_bpf_prog_info(env, info_node);
> + __perf_env__insert_bpf_prog_info(env, info_node);
> }
>
> up_write(&env->bpf_progs.lock);
> @@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
> if (__do_read(ff, node->data, data_size))
> goto out;
>
> - perf_env__insert_btf(env, node);
> + __perf_env__insert_btf(env, node);
> node = NULL;
> }
>
> --
> 2.43.0.rc2.451.g8631bc7472-goog
>

--

- Arnaldo

2024-01-03 16:24:57

by Ian Rogers

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

On Wed, Jan 3, 2024 at 8:09 AM Arnaldo Carvalho de Melo <[email protected]> wrote:
>
> Em Wed, Dec 06, 2023 at 05:46:55PM -0800, Ian Rogers escreveu:
> > Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> > and perf_env__find_btf prefixed with __ to indicate the
> > env->bpf_progs.lock is assumed held. Call these variants when the lock
> > is held to avoid recursively taking it and potentially having a thread
> > deadlock with itself.
> >
> > Signed-off-by: Ian Rogers <[email protected]>
> > ---
> > Previously this patch was part of a larger set:
> > https://lore.kernel.org/lkml/[email protected]/
> > ---
> > tools/perf/util/bpf-event.c | 8 +++---
> > tools/perf/util/bpf-event.h | 12 ++++-----
> > tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
> > tools/perf/util/env.h | 4 +++
> > tools/perf/util/header.c | 8 +++---
> > 5 files changed, 51 insertions(+), 34 deletions(-)
> >
> > diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> > index 830711cae30d..3573e0b7ef3e 100644
> > --- a/tools/perf/util/bpf-event.c
> > +++ b/tools/perf/util/bpf-event.c
> > @@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
> > return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
> > }
> >
> > -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > - struct perf_env *env,
> > - FILE *fp)
> > +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > + struct perf_env *env,
> > + FILE *fp)
> > {
> > __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
> > __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
> > @@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > if (info->btf_id) {
> > struct btf_node *node;
> >
> > - node = perf_env__find_btf(env, info->btf_id);
> > + node = __perf_env__find_btf(env, info->btf_id);
> > if (node)
> > btf = btf__new((__u8 *)(node->data),
> > node->data_size);
> > diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> > index 1bcbd4fb6c66..e2f0420905f5 100644
> > --- a/tools/perf/util/bpf-event.h
> > +++ b/tools/perf/util/bpf-event.h
> > @@ -33,9 +33,9 @@ struct btf_node {
> > int machine__process_bpf(struct machine *machine, union perf_event *event,
> > struct perf_sample *sample);
> > int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
> > -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > - struct perf_env *env,
> > - FILE *fp);
> > +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > + struct perf_env *env,
> > + FILE *fp);
> > #else
> > static inline int machine__process_bpf(struct machine *machine __maybe_unused,
> > union perf_event *event __maybe_unused,
> > @@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
> > return 0;
> > }
> >
> > -static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> > - struct perf_env *env __maybe_unused,
> > - FILE *fp __maybe_unused)
> > +static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> > + struct perf_env *env __maybe_unused,
> > + FILE *fp __maybe_unused)
> > {
> >
> > }
> > diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> > index c68b7a004f29..cfdacbf29456 100644
> > --- a/tools/perf/util/env.c
> > +++ b/tools/perf/util/env.c
> > @@ -22,15 +22,20 @@ struct perf_env perf_env;
> > #include "bpf-utils.h"
> > #include <bpf/libbpf.h>
> >
> > -void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > - struct bpf_prog_info_node *info_node)
> > +void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> > +{
> > + down_write(&env->bpf_progs.lock);
> > + __perf_env__insert_bpf_prog_info(env, info_node);
> > + up_write(&env->bpf_progs.lock);
> > +}
>
> Minor nit/modification:
>
> diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> index cfdacbf294566c33..a459374d0a1a1dc8 100644
> --- a/tools/perf/util/env.c
> +++ b/tools/perf/util/env.c
> @@ -22,7 +22,8 @@ struct perf_env perf_env;
> #include "bpf-utils.h"
> #include <bpf/libbpf.h>
>
> -void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> +void perf_env__insert_bpf_prog_info(struct perf_env *env,
> + struct bpf_prog_info_node *info_node)
> {
> down_write(&env->bpf_progs.lock);
> __perf_env__insert_bpf_prog_info(env, info_node);
>
> Just to reduce patch size a bit, just like happened with
> perf_env__insert_btf() further down, where its body was changed to call
> the __ variant but the non __ function got just the body modified.
>
> - Arnaldo

Sorry for that and thanks for the fix.

Ian

> > +void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> > {
> > __u32 prog_id = info_node->info_linear->info.id;
> > struct bpf_prog_info_node *node;
> > struct rb_node *parent = NULL;
> > struct rb_node **p;
> >
> > - down_write(&env->bpf_progs.lock);
> > p = &env->bpf_progs.infos.rb_node;
> >
> > while (*p != NULL) {
> > @@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > p = &(*p)->rb_right;
> > } else {
> > pr_debug("duplicated bpf prog info %u\n", prog_id);
> > - goto out;
> > + return;
> > }
> > }
> >
> > rb_link_node(&info_node->rb_node, parent, p);
> > rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
> > env->bpf_progs.infos_cnt++;
> > -out:
> > - up_write(&env->bpf_progs.lock);
> > }
> >
> > struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > @@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > }
> >
> > bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > +{
> > + bool ret;
> > +
> > + down_write(&env->bpf_progs.lock);
> > + ret = __perf_env__insert_btf(env, btf_node);
> > + up_write(&env->bpf_progs.lock);
> > + return ret;
> > +}
> > +
> > +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > {
> > struct rb_node *parent = NULL;
> > __u32 btf_id = btf_node->id;
> > struct btf_node *node;
> > struct rb_node **p;
> > - bool ret = true;
> >
> > - down_write(&env->bpf_progs.lock);
> > p = &env->bpf_progs.btfs.rb_node;
> >
> > while (*p != NULL) {
> > @@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > p = &(*p)->rb_right;
> > } else {
> > pr_debug("duplicated btf %u\n", btf_id);
> > - ret = false;
> > - goto out;
> > + return false;
> > }
> > }
> >
> > rb_link_node(&btf_node->rb_node, parent, p);
> > rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
> > env->bpf_progs.btfs_cnt++;
> > -out:
> > - up_write(&env->bpf_progs.lock);
> > - return ret;
> > + return true;
> > }
> >
> > struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > +{
> > + struct btf_node *res;
> > +
> > + down_read(&env->bpf_progs.lock);
> > + res = __perf_env__find_btf(env, btf_id);
> > + up_read(&env->bpf_progs.lock);
> > + return res;
> > +}
> > +
> > +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > {
> > struct btf_node *node = NULL;
> > struct rb_node *n;
> >
> > - down_read(&env->bpf_progs.lock);
> > n = env->bpf_progs.btfs.rb_node;
> >
> > while (n) {
> > @@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > else if (btf_id > node->id)
> > n = n->rb_right;
> > else
> > - goto out;
> > + return node;
> > }
> > - node = NULL;
> > -
> > -out:
> > - up_read(&env->bpf_progs.lock);
> > - return node;
> > + return NULL;
> > }
> >
> > /* purge data in bpf_progs.infos tree */
> > diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> > index bf7e3c4c211f..7c527e65c186 100644
> > --- a/tools/perf/util/env.h
> > +++ b/tools/perf/util/env.h
> > @@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
> > int perf_env__nr_cpus_avail(struct perf_env *env);
> >
> > void perf_env__init(struct perf_env *env);
> > +void __perf_env__insert_bpf_prog_info(struct perf_env *env,
> > + struct bpf_prog_info_node *info_node);
> > void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > struct bpf_prog_info_node *info_node);
> > struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > __u32 prog_id);
> > bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> > +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> > struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> > +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> >
> > int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
> > char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
> > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> > index 08cc2febabde..02bf9d8b5f74 100644
> > --- a/tools/perf/util/header.c
> > +++ b/tools/perf/util/header.c
> > @@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
> > node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> > next = rb_next(&node->rb_node);
> >
> > - bpf_event__print_bpf_prog_info(&node->info_linear->info,
> > - env, fp);
> > + __bpf_event__print_bpf_prog_info(&node->info_linear->info,
> > + env, fp);
> > }
> >
> > up_read(&env->bpf_progs.lock);
> > @@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
> > /* after reading from file, translate offset to address */
> > bpil_offs_to_addr(info_linear);
> > info_node->info_linear = info_linear;
> > - perf_env__insert_bpf_prog_info(env, info_node);
> > + __perf_env__insert_bpf_prog_info(env, info_node);
> > }
> >
> > up_write(&env->bpf_progs.lock);
> > @@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
> > if (__do_read(ff, node->data, data_size))
> > goto out;
> >
> > - perf_env__insert_btf(env, node);
> > + __perf_env__insert_btf(env, node);
> > node = NULL;
> > }
> >
> > --
> > 2.43.0.rc2.451.g8631bc7472-goog
> >
>
> --
>
> - Arnaldo

2024-01-03 16:27:30

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

Em Tue, Jan 02, 2024 at 07:00:53PM -0800, Ian Rogers escreveu:
> On Wed, Dec 6, 2023 at 5:46 PM Ian Rogers <[email protected]> wrote:
> >
> > Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> > and perf_env__find_btf prefixed with __ to indicate the
> > env->bpf_progs.lock is assumed held. Call these variants when the lock
> > is held to avoid recursively taking it and potentially having a thread
> > deadlock with itself.
> >
> > Signed-off-by: Ian Rogers <[email protected]>
>
> Ping.

Applied, with that minor patch reduction hunk and this:

Fixes: f8dfeae009effc0b ("perf bpf: Show more BPF program info in print_bpf_prog_info()")

Song, can I have your Acked-by?

- Arnaldo

>
> > ---
> > Previously this patch was part of a larger set:
> > https://lore.kernel.org/lkml/[email protected]/
> > ---
> > tools/perf/util/bpf-event.c | 8 +++---
> > tools/perf/util/bpf-event.h | 12 ++++-----
> > tools/perf/util/env.c | 53 +++++++++++++++++++++++--------------
> > tools/perf/util/env.h | 4 +++
> > tools/perf/util/header.c | 8 +++---
> > 5 files changed, 51 insertions(+), 34 deletions(-)
> >
> > diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> > index 830711cae30d..3573e0b7ef3e 100644
> > --- a/tools/perf/util/bpf-event.c
> > +++ b/tools/perf/util/bpf-event.c
> > @@ -545,9 +545,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
> > return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
> > }
> >
> > -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > - struct perf_env *env,
> > - FILE *fp)
> > +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > + struct perf_env *env,
> > + FILE *fp)
> > {
> > __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
> > __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
> > @@ -563,7 +563,7 @@ void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > if (info->btf_id) {
> > struct btf_node *node;
> >
> > - node = perf_env__find_btf(env, info->btf_id);
> > + node = __perf_env__find_btf(env, info->btf_id);
> > if (node)
> > btf = btf__new((__u8 *)(node->data),
> > node->data_size);
> > diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
> > index 1bcbd4fb6c66..e2f0420905f5 100644
> > --- a/tools/perf/util/bpf-event.h
> > +++ b/tools/perf/util/bpf-event.h
> > @@ -33,9 +33,9 @@ struct btf_node {
> > int machine__process_bpf(struct machine *machine, union perf_event *event,
> > struct perf_sample *sample);
> > int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env);
> > -void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > - struct perf_env *env,
> > - FILE *fp);
> > +void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
> > + struct perf_env *env,
> > + FILE *fp);
> > #else
> > static inline int machine__process_bpf(struct machine *machine __maybe_unused,
> > union perf_event *event __maybe_unused,
> > @@ -50,9 +50,9 @@ static inline int evlist__add_bpf_sb_event(struct evlist *evlist __maybe_unused,
> > return 0;
> > }
> >
> > -static inline void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> > - struct perf_env *env __maybe_unused,
> > - FILE *fp __maybe_unused)
> > +static inline void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info __maybe_unused,
> > + struct perf_env *env __maybe_unused,
> > + FILE *fp __maybe_unused)
> > {
> >
> > }
> > diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
> > index c68b7a004f29..cfdacbf29456 100644
> > --- a/tools/perf/util/env.c
> > +++ b/tools/perf/util/env.c
> > @@ -22,15 +22,20 @@ struct perf_env perf_env;
> > #include "bpf-utils.h"
> > #include <bpf/libbpf.h>
> >
> > -void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > - struct bpf_prog_info_node *info_node)
> > +void perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> > +{
> > + down_write(&env->bpf_progs.lock);
> > + __perf_env__insert_bpf_prog_info(env, info_node);
> > + up_write(&env->bpf_progs.lock);
> > +}
> > +
> > +void __perf_env__insert_bpf_prog_info(struct perf_env *env, struct bpf_prog_info_node *info_node)
> > {
> > __u32 prog_id = info_node->info_linear->info.id;
> > struct bpf_prog_info_node *node;
> > struct rb_node *parent = NULL;
> > struct rb_node **p;
> >
> > - down_write(&env->bpf_progs.lock);
> > p = &env->bpf_progs.infos.rb_node;
> >
> > while (*p != NULL) {
> > @@ -42,15 +47,13 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > p = &(*p)->rb_right;
> > } else {
> > pr_debug("duplicated bpf prog info %u\n", prog_id);
> > - goto out;
> > + return;
> > }
> > }
> >
> > rb_link_node(&info_node->rb_node, parent, p);
> > rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
> > env->bpf_progs.infos_cnt++;
> > -out:
> > - up_write(&env->bpf_progs.lock);
> > }
> >
> > struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > @@ -79,14 +82,22 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > }
> >
> > bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > +{
> > + bool ret;
> > +
> > + down_write(&env->bpf_progs.lock);
> > + ret = __perf_env__insert_btf(env, btf_node);
> > + up_write(&env->bpf_progs.lock);
> > + return ret;
> > +}
> > +
> > +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > {
> > struct rb_node *parent = NULL;
> > __u32 btf_id = btf_node->id;
> > struct btf_node *node;
> > struct rb_node **p;
> > - bool ret = true;
> >
> > - down_write(&env->bpf_progs.lock);
> > p = &env->bpf_progs.btfs.rb_node;
> >
> > while (*p != NULL) {
> > @@ -98,25 +109,31 @@ bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
> > p = &(*p)->rb_right;
> > } else {
> > pr_debug("duplicated btf %u\n", btf_id);
> > - ret = false;
> > - goto out;
> > + return false;
> > }
> > }
> >
> > rb_link_node(&btf_node->rb_node, parent, p);
> > rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
> > env->bpf_progs.btfs_cnt++;
> > -out:
> > - up_write(&env->bpf_progs.lock);
> > - return ret;
> > + return true;
> > }
> >
> > struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > +{
> > + struct btf_node *res;
> > +
> > + down_read(&env->bpf_progs.lock);
> > + res = __perf_env__find_btf(env, btf_id);
> > + up_read(&env->bpf_progs.lock);
> > + return res;
> > +}
> > +
> > +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > {
> > struct btf_node *node = NULL;
> > struct rb_node *n;
> >
> > - down_read(&env->bpf_progs.lock);
> > n = env->bpf_progs.btfs.rb_node;
> >
> > while (n) {
> > @@ -126,13 +143,9 @@ struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
> > else if (btf_id > node->id)
> > n = n->rb_right;
> > else
> > - goto out;
> > + return node;
> > }
> > - node = NULL;
> > -
> > -out:
> > - up_read(&env->bpf_progs.lock);
> > - return node;
> > + return NULL;
> > }
> >
> > /* purge data in bpf_progs.infos tree */
> > diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
> > index bf7e3c4c211f..7c527e65c186 100644
> > --- a/tools/perf/util/env.h
> > +++ b/tools/perf/util/env.h
> > @@ -175,12 +175,16 @@ const char *perf_env__raw_arch(struct perf_env *env);
> > int perf_env__nr_cpus_avail(struct perf_env *env);
> >
> > void perf_env__init(struct perf_env *env);
> > +void __perf_env__insert_bpf_prog_info(struct perf_env *env,
> > + struct bpf_prog_info_node *info_node);
> > void perf_env__insert_bpf_prog_info(struct perf_env *env,
> > struct bpf_prog_info_node *info_node);
> > struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
> > __u32 prog_id);
> > bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> > +bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
> > struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> > +struct btf_node *__perf_env__find_btf(struct perf_env *env, __u32 btf_id);
> >
> > int perf_env__numa_node(struct perf_env *env, struct perf_cpu cpu);
> > char *perf_env__find_pmu_cap(struct perf_env *env, const char *pmu_name,
> > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> > index 08cc2febabde..02bf9d8b5f74 100644
> > --- a/tools/perf/util/header.c
> > +++ b/tools/perf/util/header.c
> > @@ -1849,8 +1849,8 @@ static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
> > node = rb_entry(next, struct bpf_prog_info_node, rb_node);
> > next = rb_next(&node->rb_node);
> >
> > - bpf_event__print_bpf_prog_info(&node->info_linear->info,
> > - env, fp);
> > + __bpf_event__print_bpf_prog_info(&node->info_linear->info,
> > + env, fp);
> > }
> >
> > up_read(&env->bpf_progs.lock);
> > @@ -3188,7 +3188,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
> > /* after reading from file, translate offset to address */
> > bpil_offs_to_addr(info_linear);
> > info_node->info_linear = info_linear;
> > - perf_env__insert_bpf_prog_info(env, info_node);
> > + __perf_env__insert_bpf_prog_info(env, info_node);
> > }
> >
> > up_write(&env->bpf_progs.lock);
> > @@ -3235,7 +3235,7 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
> > if (__do_read(ff, node->data, data_size))
> > goto out;
> >
> > - perf_env__insert_btf(env, node);
> > + __perf_env__insert_btf(env, node);
> > node = NULL;
> > }
> >
> > --
> > 2.43.0.rc2.451.g8631bc7472-goog
> >
>

--

- Arnaldo

2024-01-03 17:41:49

by Song Liu

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

On Wed, Jan 3, 2024 at 8:27 AM Arnaldo Carvalho de Melo <[email protected]> wrote:
>
> Em Tue, Jan 02, 2024 at 07:00:53PM -0800, Ian Rogers escreveu:
> > On Wed, Dec 6, 2023 at 5:46 PM Ian Rogers <[email protected]> wrote:
> > >
> > > Add variants of perf_env__insert_bpf_prog_info, perf_env__insert_btf
> > > and perf_env__find_btf prefixed with __ to indicate the
> > > env->bpf_progs.lock is assumed held. Call these variants when the lock
> > > is held to avoid recursively taking it and potentially having a thread
> > > deadlock with itself.
> > >
> > > Signed-off-by: Ian Rogers <[email protected]>
> >
> > Ping.
>
> Applied, with that minor patch reduction hunk and this:
>
> Fixes: f8dfeae009effc0b ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
>
> Song, can I have your Acked-by?

LGTM. Thanks for the fix!

Acked-by: Song Liu <[email protected]>

2024-01-03 20:55:45

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v1] perf env: Avoid recursively taking env->bpf_progs.lock

Em Wed, Jan 03, 2024 at 09:40:26AM -0800, Song Liu escreveu:
> On Wed, Jan 3, 2024 at 8:27 AM Arnaldo Carvalho de Melo <[email protected]> wrote:
> > Applied, with that minor patch reduction hunk and this:

> > Fixes: f8dfeae009effc0b ("perf bpf: Show more BPF program info in print_bpf_prog_info()")

> > Song, can I have your Acked-by?

> LGTM. Thanks for the fix!

> Acked-by: Song Liu <[email protected]>

Thanks! Added to the cset.

- Arnaldo