[PATCH v2] uprobes: fix incorrect lockdep condition in filter_chain()

[PATCH v2] uprobes: fix incorrect lockdep condition in filter_chain()

[Breno Leitao]

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: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under SRCU protection")
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changes in v2:
- updated the "fixes" tag (Oleg)
- Link to v1: https://patch.msgid.link/20260128-uprobe_rcu-v1-1-d41316763799@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 <leitao@debian.org>

Re: [PATCH v2] uprobes: fix incorrect lockdep condition in filter_chain()

[Masami Hiramatsu]

On Wed, 28 Jan 2026 10:16:11 -0800
Breno Leitao <leitao@debian.org> wrote:

> 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.
> 

Looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

> Cc: stable@vger.kernel.org
> Fixes: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under SRCU protection")
> Acked-by: Oleg Nesterov <oleg@redhat.com>
> Acked-by: Andrii Nakryiko <andrii@kernel.org>
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
> Changes in v2:
> - updated the "fixes" tag (Oleg)
> - Link to v1: https://patch.msgid.link/20260128-uprobe_rcu-v1-1-d41316763799@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 <leitao@debian.org>
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

[tip: perf/core] uprobes: Fix incorrect lockdep condition in filter_chain()

[tip-bot2 for Breno Leitao]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     a56a38fd9196fc89401e498d70b7aa9c9679fa6e
Gitweb:        https://git.kernel.org/tip/a56a38fd9196fc89401e498d70b7aa9c9679fa6e
Author:        Breno Leitao <leitao@debian.org>
AuthorDate:    Wed, 28 Jan 2026 10:16:11 -08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 02 Feb 2026 22:01:07 +01:00

uprobes: Fix incorrect lockdep condition in filter_chain()

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.

Fixes: cc01bd044e6a ("uprobes: travers uprobe's consumer list locklessly under SRCU protection")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260128-uprobe_rcu-v2-1-994ea6d32730@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 dfbce02..424ef22 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;