linux-kernel - [BUG] drbd/block: A sleep-in-atomic bug in notify

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Date:   Wed, 4 Oct 2017 09:39:24 +0800
From:   Jia-Ju Bai <baijiaju1990@....com>
To:     philipp.reisner@...bit.com, lars.ellenberg@...bit.com
Cc:     drbd-dev@...ts.linbit.com, linux-kernel@...r.kernel.org
Subject: [BUG] drbd/block: A sleep-in-atomic bug in notify_helper

The driver may sleep under a RCU lock, and the function call path is:
drbd_sync_handshake (acquire the RCU lock)
   drbd_asb_recover_1p
     drbd_khelper
       notify_helper
         mutex_lock --> may sleep

I hope to fix it, but I do not find a proper way at present ...
This bug is found by my static analysis tool and my code review.


Thanks,
Jia-Ju Bai