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From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: ccaulfie@redhat.com, teigland@redhat.com
Cc: cluster-devel@redhat.com, linux-kernel <linux-kernel@vger.kernel.org>
Subject: [BUG] fs: dlm: possible ABBA deadlock
Date: Thu, 19 Aug 2021 16:54:57 +0800	[thread overview]
Message-ID: <79f8d302-f53f-3891-965a-bcb460ab15ca@gmail.com> (raw)

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 :)

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>


Best wishes,
Jia-Ju Bai

WARNING: multiple messages have this Message-ID (diff)
From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [BUG] fs: dlm: possible ABBA deadlock
Date: Thu, 19 Aug 2021 16:54:57 +0800	[thread overview]
Message-ID: <79f8d302-f53f-3891-965a-bcb460ab15ca@gmail.com> (raw)

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 :)

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>


Best wishes,
Jia-Ju Bai



             reply	other threads:[~2021-08-19  8:55 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19  8:54 Jia-Ju Bai [this message]
2021-08-19  8:54 ` [Cluster-devel] [BUG] fs: dlm: possible ABBA deadlock Jia-Ju Bai
2021-08-19 15:55 ` David Teigland
2021-08-19 15:55   ` [Cluster-devel] " David Teigland
2021-08-20  8:16   ` Jia-Ju Bai
2021-08-20  8:16     ` [Cluster-devel] " Jia-Ju Bai

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