6.12-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Antipov dmantipov@yandex.ru
commit 40ee2afafc1d9fe3aa44a6fbe440d78a5c96a72e upstream.
Enlarge the critical section in ring_buffer_subbuf_order_set() to ensure that error handling takes place with per-buffer mutex held, thus preventing list corruption and other concurrency-related issues.
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Tzvetomir Stoyanov tz.stoyanov@gmail.com Link: https://lore.kernel.org/20250606112242.1510605-1-dmantipov@yandex.ru Reported-by: syzbot+05d673e83ec640f0ced9@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=05d673e83ec640f0ced9 Fixes: f9b94daa542a8 ("ring-buffer: Set new size of the ring buffer sub page") Signed-off-by: Dmitry Antipov dmantipov@yandex.ru Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/ring_buffer.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6754,7 +6754,7 @@ int ring_buffer_subbuf_order_set(struct old_size = buffer->subbuf_size;
/* prevent another thread from changing buffer sizes */ - mutex_lock(&buffer->mutex); + guard(mutex)(&buffer->mutex); atomic_inc(&buffer->record_disabled);
/* Make sure all commits have finished */ @@ -6859,7 +6859,6 @@ int ring_buffer_subbuf_order_set(struct }
atomic_dec(&buffer->record_disabled); - mutex_unlock(&buffer->mutex);
return 0;
@@ -6868,7 +6867,6 @@ error: buffer->subbuf_size = old_size;
atomic_dec(&buffer->record_disabled); - mutex_unlock(&buffer->mutex);
for_each_buffer_cpu(buffer, cpu) { cpu_buffer = buffer->buffers[cpu];