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authorBreno Leitao <leitao@debian.org>2025-01-17 06:41:07 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-07 18:25:38 +0100
commita2475ccad6120546ea45dbcd6cd1f74dc565ef6b (patch)
tree55fc5c2d02a8870562f1e2aef0cbb1afe1a80343 /kernel
parentb9de147b2ccb3532d0dc1837ca8ff1b90028b941 (diff)
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perf/core: Add RCU read lock protection to perf_iterate_ctx()
commit 0fe8813baf4b2e865d3b2c735ce1a15b86002c74 upstream. The perf_iterate_ctx() function performs RCU list traversal but currently lacks RCU read lock protection. This causes lockdep warnings when running perf probe with unshare(1) under CONFIG_PROVE_RCU_LIST=y: WARNING: suspicious RCU usage kernel/events/core.c:8168 RCU-list traversed in non-reader section!! Call Trace: lockdep_rcu_suspicious ? perf_event_addr_filters_apply perf_iterate_ctx perf_event_exec begin_new_exec ? load_elf_phdrs load_elf_binary ? lock_acquire ? find_held_lock ? bprm_execve bprm_execve do_execveat_common.isra.0 __x64_sys_execve do_syscall_64 entry_SYSCALL_64_after_hwframe This protection was previously present but was removed in commit bd2756811766 ("perf: Rewrite core context handling"). Add back the necessary rcu_read_lock()/rcu_read_unlock() pair around perf_iterate_ctx() call in perf_event_exec(). [ mingo: Use scoped_guard() as suggested by Peter ] Fixes: bd2756811766 ("perf: Rewrite core context handling") Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250117-fix_perf_rcu-v1-1-13cb9210fc6a@debian.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 07cd2dbab0e8..a3db8f859c7a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8240,7 +8240,8 @@ void perf_event_exec(void)
perf_event_enable_on_exec(ctx);
perf_event_remove_on_exec(ctx);
- perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
+ scoped_guard(rcu)
+ perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
perf_unpin_context(ctx);
put_ctx(ctx);