From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3557428A1C3; Fri, 6 Jun 2025 16:42:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749228152; cv=none; b=PBYE+EuiQKoLmm5+qEmGKaV9uH3mfprvnOTcm5Kt9n9+m7Km+fZqCPmh2BwyW5il2QKA+M+kcwLfRDM2quDye7T5G3rBEN2eECdr1BRm38K1cTiD0dcbw8L7w5w98k92aLAq1XB9nUKvxF2CVDV0vZgxds933fZwwX0Ot4H8ydo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749228152; c=relaxed/simple; bh=bup0VwhlRIh0zyMHrfXhnPPznLi8Kh/TsT1pQRvseL0=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=sI2TMz8RxenVYad/UX+2Wok7WYCktsoZdlDiw3G/Nnq3OjNGZ3TOO6+vvygwbUjfLCjGCgLTL3yd53TwfnztjRe2GQO2L84awZ18sXLcIcy44CchssPnSxE4cFNEGQHqxeF1/vG6sKX0MaQjnsZnNmHu9bdDhCYsQYIDa93DoU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DCEF3C4CEF6; Fri, 6 Jun 2025 16:42:31 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98.2) (envelope-from ) id 1uNaAb-0000000FxAu-2a8Y; Fri, 06 Jun 2025 12:43:53 -0400 Message-ID: <20250606164353.472136191@goodmis.org> User-Agent: quilt/0.68 Date: Fri, 06 Jun 2025 12:42:31 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Tzvetomir Stoyanov , syzbot+05d673e83ec640f0ced9@syzkaller.appspotmail.com, Dmitry Antipov Subject: [for-linus][PATCH 2/3] ring-buffer: Fix buffer locking in ring_buffer_subbuf_order_set() References: <20250606164229.056794577@goodmis.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Dmitry Antipov 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 Cc: Mathieu Desnoyers Cc: Tzvetomir Stoyanov 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 Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index e24509bd0af5..00fc38d70e86 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6795,7 +6795,7 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) 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 */ @@ -6900,7 +6900,6 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) } atomic_dec(&buffer->record_disabled); - mutex_unlock(&buffer->mutex); return 0; @@ -6909,7 +6908,6 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) 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]; -- 2.47.2