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Date:   Mon, 13 Jun 2022 17:03:29 -0700
From:   "Paul E. McKenney" <paulmck@kernel.org>
To:     Kees Cook <keescook@chromium.org>
Cc:     "Zhang, Qiang1" <qiang1.zhang@intel.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        syzbot <syzbot+9bb26e7c5e8e4fa7e641@syzkaller.appspotmail.com>,
        "brauner@kernel.org" <brauner@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "syzkaller-bugs@googlegroups.com" <syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] WARNING in exit_tasks_rcu_finish
Message-ID: <20220614000329.GO1790663@paulmck-ThinkPad-P17-Gen-1>
Reply-To: paulmck@kernel.org
References: <20220613233753.GK1790663@paulmck-ThinkPad-P17-Gen-1>
 <202206131639.DBA0A8D@keescook>
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On Mon, Jun 13, 2022 at 04:42:07PM -0700, Kees Cook wrote:
> On Mon, Jun 13, 2022 at 10:36:07AM -0700, syzbot wrote:
> > Hello,
> > 
> > syzbot has tested the proposed patch and the reproducer did not trigger any issue:
> > 
> > Reported-and-tested-by: syzbot+9bb26e7c5e8e4fa7e641@syzkaller.appspotmail.com
> 
> Looks like the patch solved the reproducer. :)

For one of the two possible ways to make the bug happen.  ;-)

Still, good on Qiang for identifying one of the paths!  Not just anyone
can do that.

							Thanx, Paul

> > Tested on:
> > 
> > commit:         6d0c8068 Add linux-next specific files for 20220610
> > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git next-20220610
> > console output: https://syzkaller.appspot.com/x/log.txt?x=12d068eff00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=a30d6e3e814e5931
> > dashboard link: https://syzkaller.appspot.com/bug?extid=9bb26e7c5e8e4fa7e641
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > patch:          https://syzkaller.appspot.com/x/patch.diff?x=147f47c8080000
> > 
> > Note: testing is done by a robot and is best-effort only.
> 
> You can see the dashboard link above for testing details...
> 
> -- 
> Kees Cook