From: Oleg Nesterov <oleg@redhat.com>
To: Hillf Danton <hdanton@sina.com>
Cc: Namhyung Kim <namhyung@kernel.org>,
Song Liu <songliubraving@fb.com>,
Peter Zijlstra <peterz@infradead.org>,
syzbot <syzbot+b804f902bbb6bcf290cb@syzkaller.appspotmail.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Greg KH <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] possible deadlock in register_for_each_vma
Date: Thu, 1 Apr 2021 12:53:26 +0200 [thread overview]
Message-ID: <20210401105305.GA18680@redhat.com> (raw)
In-Reply-To: <20210401092907.1098-1-hdanton@sina.com>
On 04/01, Hillf Danton wrote:
>
> If I dont misread it, the lockdep chain will likely evolve from
>
> event_mutex -> uprobe.register_rwsem -> dup_mmap_sem -> mm.mmap_lock ->
> event_mutex
> to
> dup_mmap_sem -> mm.mmap_lock -> dup_mmap_sem
>
> after this patch as both uprobe_register() and uprobe_unregister() would take
> dup_mmap_sem.
Hmm, please correct me, but I don't think so. I think mmap_lock -> dup_mmap_sem
is not possible.
Oleg.
next prev parent reply other threads:[~2021-04-01 10:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 10:29 [syzbot] possible deadlock in register_for_each_vma syzbot
[not found] ` <20210327042150.7460-1-hdanton@sina.com>
2021-03-27 17:53 ` Oleg Nesterov
[not found] ` <20210328025217.7312-1-hdanton@sina.com>
2021-03-31 16:59 ` Oleg Nesterov
2021-03-31 20:18 ` Song Liu
[not found] ` <20210401092907.1098-1-hdanton@sina.com>
2021-04-01 10:53 ` Oleg Nesterov [this message]
[not found] ` <20210402074636.1270-1-hdanton@sina.com>
2021-04-06 17:23 ` perf_mmap_close() -> put_event() -> event.destroy() can deadlock Oleg Nesterov
2021-04-06 17:43 ` perf_buffer.event_list is not RCU-safe? Oleg Nesterov
2021-04-07 7:50 ` Peter Zijlstra
2021-04-07 12:30 ` Oleg Nesterov
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