From: Steven Rostedt <rostedt@goodmis.org>
To: Denis Efremov <efremov@linux.com>
Cc: Gaurav Kohli <gkohli@codeaurora.org>,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v1] trace: Fix race in trace_open and buffer resize call
Date: Thu, 21 Jan 2021 14:09:51 -0500 [thread overview]
Message-ID: <20210121140951.2a554a5e@gandalf.local.home> (raw)
In-Reply-To: <f06efd7b-c7b5-85c9-1a0e-6bb865111ede@linux.com>
On Thu, 21 Jan 2021 17:30:40 +0300
Denis Efremov <efremov@linux.com> wrote:
> Hi,
>
> This patch (CVE-2020-27825) was tagged with
> Fixes: b23d7a5f4a07a ("ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU")
>
> I'm not an expert here but it seems like b23d7a5f4a07a only refactored
> ring_buffer_reset_cpu() by introducing reset_disabled_cpu_buffer() without
> significant changes. Hence, mutex_lock(&buffer->mutex)/mutex_unlock(&buffer->mutex)
> can be backported further than b23d7a5f4a07a~ and to all LTS kernels. Is
> b23d7a5f4a07a the actual cause of the bug?
>
Ug, that looks to be a mistake. Looking back at the thread about this:
https://lore.kernel.org/linux-arm-msm/20200915141304.41fa7c30@gandalf.local.home/
That should have been:
Depends-on: b23d7a5f4a07 ("ring-buffer: speed up buffer resets by avoiding synchronize_rcu for each CPU")
-- Steve
next prev parent reply other threads:[~2021-01-21 19:11 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 9:33 [PATCH v1] trace: Fix race in trace_open and buffer resize call Gaurav Kohli
2021-01-21 14:30 ` Denis Efremov
2021-01-21 19:09 ` Steven Rostedt [this message]
2021-01-21 20:15 ` Denis Efremov
2021-01-21 20:37 ` Steven Rostedt
2021-01-22 10:59 ` Greg KH
2021-01-22 11:25 ` Gaurav Kohli
2021-01-22 14:37 ` Steven Rostedt
2021-01-23 10:49 ` Denis Efremov
2021-01-23 16:33 ` Gaurav Kohli
2021-01-24 3:21 ` Steven Rostedt
2021-01-24 9:57 ` Gaurav Kohli
2021-01-24 10:05 ` Greg KH
-- strict thread matches above, loose matches on Subject: below --
2020-09-24 13:55 Gaurav Kohli
2020-10-05 4:39 ` Gaurav Kohli
2020-10-05 14:25 ` Steven Rostedt
2020-10-05 14:27 ` Steven Rostedt
2020-10-05 16:29 ` Gaurav Kohli
2020-10-05 16:32 ` Steven Rostedt
2020-10-05 17:38 ` Gaurav Kohli
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