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Date: Sun, 19 Nov 2023 16:30:28 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: syzbot <syzbot+cef555184e66963dabc2@syzkaller.appspotmail.com>,
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Subject: Re: [syzbot] [cgroups?] possible deadlock in cgroup_free
Message-ID: <20231119153028.GB29401@redhat.com>
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On 11/19, Tejun Heo wrote:
>
> On Thu, Nov 16, 2023 at 05:25:05PM -0800, syzbot wrote:
> > syzbot has bisected this issue to:
> >
> > commit 2d25a889601d2fbc87ec79b30ea315820f874b78
> > Author: Peter Zijlstra <peterz@infradead.org>
> > Date:   Sun Sep 17 11:24:21 2023 +0000
> >
> >     ptrace: Convert ptrace_attach() to use lock guards
>
> Looks like the tasklist_lock conversion in ptrace_attach() forgot _irq.
> Peter, Oleg?

Yes, please see

	Re: [syzbot] [kernel?] inconsistent lock state in ptrace_attach
	https://lore.kernel.org/all/20231117094531.GN8262@noisy.programming.kicks-ass.net/

Oleg.