From nobody Sat Feb 7 13:45:46 2026 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 2E1F81DDF5; Fri, 16 Aug 2024 12:16:14 +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=1723810574; cv=none; b=Vv1XBpitTBp3a196BNQB/f/+AV4bEmDiQ7xg6RbWgNEq93G4XannfSUpslhhZDn6haZTeGzHc8PikusIWaEN6NqxtYjVNGNL/giE200HAEsDuyLK0Cxvrm2Js6WFSBz/f/F1x1+AdyQGAps2H3iFYbNJE2ay0meWfgWRGyXZnRM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723810574; c=relaxed/simple; bh=Q7WS1g7YwS/9CWfzKsjizF2Vxs4gQnYfnFdhZbKb38k=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=Qz+BVZRfrTCC8k4VhejWmBWvRL3ZNMUMNWRl/dQY6yXXd2EDuGKTYTYqRpL438N0jUECpWk7ZmOOy9PQbf6ILucsn69f6w5ddEIKAWkRWNmWgxWEoz/8Yea34iNutMt4toFIUP65Y7gVy3bzQcTu6wiZZkvVpyv1eLyh9JLTkfg= 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 F3D50C4AF09; Fri, 16 Aug 2024 12:16:13 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1sevse-000000024Bi-13ud; Fri, 16 Aug 2024 08:16:32 -0400 Message-ID: <20240816121632.119157839@goodmis.org> User-Agent: quilt/0.68 Date: Fri, 16 Aug 2024 08:16:12 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org Subject: [for-linus][PATCH 1/2] tracing: Return from tracing_buffers_read() if the file has been closed References: <20240816121611.805849825@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Rostedt When running the following: # cd /sys/kernel/tracing/ # echo 1 > events/sched/sched_waking/enable # echo 1 > events/sched/sched_switch/enable # echo 0 > tracing_on # dd if=3Dper_cpu/cpu0/trace_pipe_raw of=3D/tmp/raw0.dat The dd task would get stuck in an infinite loop in the kernel. What would happen is the following: When ring_buffer_read_page() returns -1 (no data) then a check is made to see if the buffer is empty (as happens when the page is not full), it will call wait_on_pipe() to wait until the ring buffer has data. When it is it will try again to read data (unless O_NONBLOCK is set). The issue happens when there's a reader and the file descriptor is closed. The wait_on_pipe() will return when that is the case. But this loop will continue to try again and wait_on_pipe() will again return immediately and the loop will continue and never stop. Simply check if the file was closed before looping and exit out if it is. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/20240808235730.78bf63e5@rorschach.local.home Fixes: 2aa043a55b9a7 ("tracing/ring-buffer: Fix wait_on_pipe() race") Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 10cd38bce2f1..ebe7ce2f5f4a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -7956,7 +7956,7 @@ tracing_buffers_read(struct file *filp, char __user *= ubuf, trace_access_unlock(iter->cpu_file); =20 if (ret < 0) { - if (trace_empty(iter)) { + if (trace_empty(iter) && !iter->closed) { if ((filp->f_flags & O_NONBLOCK)) return -EAGAIN; =20 --=20 2.43.0 From nobody Sat Feb 7 13:45:46 2026 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 97E581A01CF; Fri, 16 Aug 2024 12:16:14 +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=1723810574; cv=none; b=XwGIjgFxcgfGru/+/sAgptH6PzHLYNKQYUXSgDxehxHAuNyiBbRfZiWQeL+r2QZybdyk7el34rwG3146kQHUzqjODIq9kt/bM4oofi/wObKknBas3TzTsDDamvQTLK309t61jJ5sFvlH8E9xXF81+IfQkstVw9O+2QZG+n4pRxU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723810574; c=relaxed/simple; bh=Bpv7EIcuRzwo5wC699g8hbXTAngWqZU6pJ/cl90AzQ0=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=cPycHzB1fvsReRasSe65HG08Mdg4N+RkRtmm2Wv4oq6euWJc4MOExWbdxgOtqHg//D4tDJFuZFRMPiXDrX0lUuWAQhXZiU3epzGijjRv7NhQnrsO3QVMhzu0NlcQUdwnbNyvepZzbKSSJwQlxgfBVN2mW3rXSa5/sLqqECYWE2g= 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 40CE9C4AF10; Fri, 16 Aug 2024 12:16:14 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1sevse-000000024CC-1if2; Fri, 16 Aug 2024 08:16:32 -0400 Message-ID: <20240816121632.274981284@goodmis.org> User-Agent: quilt/0.68 Date: Fri, 16 Aug 2024 08:16:13 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, John Kacur , "Luis Claudio R. Goncalves" , Clark Williams , Dan Carpenter Subject: [for-linus][PATCH 2/2] rtla/osnoise: Prevent NULL dereference in error handling References: <20240816121611.805849825@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Dan Carpenter If the "tool->data" allocation fails then there is no need to call osnoise_free_top() and, in fact, doing so will lead to a NULL dereference. Cc: stable@vger.kernel.org Cc: John Kacur Cc: "Luis Claudio R. Goncalves" Cc: Clark Williams Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode") Link: https://lore.kernel.org/f964ed1f-64d2-4fde-ad3e-708331f8f358@stanley.= mountain Signed-off-by: Dan Carpenter Signed-off-by: Steven Rostedt (Google) --- tools/tracing/rtla/src/osnoise_top.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/= osnoise_top.c index f594a44df840..2f756628613d 100644 --- a/tools/tracing/rtla/src/osnoise_top.c +++ b/tools/tracing/rtla/src/osnoise_top.c @@ -651,8 +651,10 @@ struct osnoise_tool *osnoise_init_top(struct osnoise_t= op_params *params) return NULL; =20 tool->data =3D osnoise_alloc_top(nr_cpus); - if (!tool->data) - goto out_err; + if (!tool->data) { + osnoise_destroy_tool(tool); + return NULL; + } =20 tool->params =3D params; =20 @@ -660,11 +662,6 @@ struct osnoise_tool *osnoise_init_top(struct osnoise_t= op_params *params) osnoise_top_handler, NULL); =20 return tool; - -out_err: - osnoise_free_top(tool->data); - osnoise_destroy_tool(tool); - return NULL; } =20 static int stop_tracing; --=20 2.43.0