Thread (4 messages) 4 messages, 3 authors, 2026-01-28

[PATCH] uprobes: fix incorrect lockdep condition in filter_chain()

From: Breno Leitao <leitao@debian.org>
Date: 2026-01-28 09:59:27
Also in: linux-perf-users, lkml, stable
Subsystem: performance events subsystem, the rest, uprobes · Maintainers: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds, Masami Hiramatsu, Oleg Nesterov

The list_for_each_entry_rcu() in filter_chain() uses
rcu_read_lock_trace_held() as the lockdep condition, but the function
holds consumer_rwsem, not the RCU trace lock.

This gives me the following output when running with some locking debug
option enabled:

  kernel/events/uprobes.c:1141 RCU-list traversed in non-reader section!!
    filter_chain
    register_for_each_vma
    uprobe_unregister_nosync
    __probe_event_disable

Remove the incorrect lockdep condition since the rwsem provides
sufficient protection for the list traversal.

Cc: stable@vger.kernel.org
Fixes: 87195a1ee332a ("uprobes: switch to RCU Tasks Trace flavor for better performance")
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 kernel/events/uprobes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index d546d32390a81..726d13b375f3d 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1138,7 +1138,7 @@ static bool filter_chain(struct uprobe *uprobe, struct mm_struct *mm)
 	bool ret = false;
 
 	down_read(&uprobe->consumer_rwsem);
-	list_for_each_entry_rcu(uc, &uprobe->consumers, cons_node, rcu_read_lock_trace_held()) {
+	list_for_each_entry(uc, &uprobe->consumers, cons_node) {
 		ret = consumer_filter(uc, mm);
 		if (ret)
 			break;

---
base-commit: 1f97d9dcf53649c41c33227b345a36902cbb08ad
change-id: 20260128-uprobe_rcu-e21867ab4c1b

Best regards,
--  
Breno Leitao [off-list ref]
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