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From:   Steven Noonan <steven.noonan@gmail.com>
Date:   Mon, 31 Oct 2022 01:29:56 -0700
Message-ID: <CACv5JCJLSJ0G0jfQnucBwE3z62s6eSAYyyWW8U6FLfgn6P0ELA@mail.gmail.com>
Subject: Re: [REGRESSION 6.0.x / 6.1.x] NULL dereferencing at tracing
To:     Takashi Iwai <tiwai@suse.de>
Cc:     Steven Rostedt <rostedt@goodmis.org>, regressions@lists.linux.dev,
        linux-kernel@vger.kernel.org
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I hit this same NULL pointer dereference on one of my systems, trying
to boot with either 6.0.6 or 5.15.76. Unfortunately it happens fairly
early in boot during network initialization, which makes it
frustrating to recover from.


On Mon, Oct 31, 2022 at 12:24 AM Takashi Iwai <tiwai@suse.de> wrote:
>
> Hi Steven,
>
> we've got a bug report indicating the NULL dereference at the recent
> tracing changes, showing at the start of KDE.  The details including
> the dmesg are found at:
>   https://bugzilla.opensuse.org/show_bug.cgi?id=1204705
>
> It was reported at first for 6.0.3, and confirmed that the problem
> persists with 6.1-rc, too.
>
> The culprit seems to be the commit
> f3ddb74ad0790030c9592229fb14d8c451f4e9a8
>     tracing: Wake up ring buffer waiters on closing of the file
> and reverting it seems fixing the problem.
>
> Could you take a look?
>
>
> thanks,
>
> Takashi