perf env: Avoid recursively taking env->bpf_progs.lock

[ Upstream commit 9c51f87 ]

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.

Fixes: f8dfeae ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20231207014655.1252484-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

tools/perf/util/bpf-event.c

@@ -442,9 +442,9 @@ int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
  return perf_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);
@@ -460,7 +460,7 @@ 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);

tools/perf/util/bpf-event.h

@@ -34,9 +34,9 @@ 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,
@@ -51,9 +51,9 @@ 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)
 {
 
 }

tools/perf/util/env.c

@@ -15,13 +15,19 @@ struct perf_env perf_env;
 
 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) {
@@ -33,15 +39,13 @@ 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,
@@ -70,14 +74,22 @@ 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) {
@@ -89,25 +101,31 @@ 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) {
@@ -117,13 +135,9 @@ 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 */

tools/perf/util/env.h

@@ -117,12 +117,16 @@ 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, int cpu);
 #endif /* __PERF_ENV_H */

tools/perf/util/header.c

@@ -1546,8 +1546,8 @@ 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);
@@ -2724,7 +2724,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
  /* after reading from file, translate offset to address */
  bpf_program__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);
@@ -2777,7 +2777,7 @@ 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;
  }