Re: [PATCH] UBI: Fix possible deadlock in erase_worker()
From: Artem Bityutskiy <dedekind1@gmail.com>
Date: 2014-09-17 08:28:34
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On Tue, 2014-09-16 at 09:48 +0200, Richard Weinberger wrote:
If sync_erase() failes with EINTR, ENOMEM, EAGAIN or EBUSY erase_worker() re-schedules the failed work. This will lead to a deadlock because erase_worker() is called with work_sem held in read mode. And schedule_erase() will take this lock again.
IIRC, the assumption was that the R/W semaphore may be taken in read mode many times, so it wouldn't hurt to do: down_read() down_read() up_read() up_read() If this is right, then the lockdep warning is incorrect. -- Best Regards, Artem Bityutskiy