From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: David Teigland <teigland@redhat.com>
Cc: cluster-devel@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [BUG] fs: dlm: possible ABBA deadlock
Date: Fri, 20 Aug 2021 16:16:02 +0800 [thread overview]
Message-ID: <fbf23736-26a7-7442-2c19-ae0bea25b296@gmail.com> (raw)
In-Reply-To: <20210819155509.GB21218@redhat.com>
On 2021/8/19 23:55, David Teigland wrote:
> On Thu, Aug 19, 2021 at 04:54:57PM +0800, Jia-Ju Bai wrote:
>> Hello,
>>
>> My static analysis tool reports a possible ABBA deadlock in the dlm
>> filesystem in Linux 5.10:
>>
>> dlm_recover_waiters_pre()
>> mutex_lock(&ls->ls_waiters_mutex); --> line 5130
>> recover_convert_waiter()
>> _receive_convert_reply()
>> lock_rsb()
>> mutex_lock(&r->res_mutex); --> line 69
>>
>> dlm_recover_waiters_post()
>> lock_rsb()
>> mutex_lock(&r->res_mutex); --> line 69
>> mutex_lock(&ls->ls_waiters_mutex); --> line 5307
>>
>> When dlm_recover_waiters_pre() and dlm_recover_waiters_post() are
>> concurrently executed, the deadlock can occur.
>>
>> I am not quite sure whether this possible deadlock is real and how to fix it
>> if it is real.
>> Any feedback would be appreciated, thanks :)
> They won't be concurrent, "pre" runs before recovery, and "post" is after.
Okay, thanks for your reply :)
Best wishes,
Jia-Ju Bai
prev parent reply other threads:[~2021-08-20 8:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-19 8:54 [BUG] fs: dlm: possible ABBA deadlock Jia-Ju Bai
2021-08-19 15:55 ` David Teigland
2021-08-20 8:16 ` Jia-Ju Bai [this message]
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