Messages in this thread | | | Date | Thu, 21 Jan 2021 14:09:51 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH v1] trace: Fix race in trace_open and buffer resize call |
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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
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