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: [email protected]
Fixes: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under
SRCU protection")
Acked-by: Oleg Nesterov <[email protected]>
Acked-by: Andrii Nakryiko <[email protected]>
Signed-off-by: Breno Leitao <[email protected]>
---
Changes in v2:
- updated the "fixes" tag (Oleg)
- Link to v1:
https://patch.msgid.link/[email protected]
---
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 <[email protected]>
