From: Pavel Machek <pavel@ucw.cz>
To: Charles Gong <cggong@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] Fix sysrq emergency thaw
Date: Fri, 5 Aug 2016 22:14:47 +0200 [thread overview]
Message-ID: <20160805201447.GC7999@amd> (raw)
In-Reply-To: <5823da614460b8c40809e6e0a6de172a9c4f4611.1468965479.git.cggong@fb.com>
On Wed 2016-07-20 16:11:16, Charles Gong wrote:
> "SYSRQ + J" triggers a call to emergency_thaw_all(). Currently, this
> is an infinite loop. Once we trigger it, we'll need to do a hard
> power-cycle. There are users reporting this bug from 2012 to 2016, for
> example, at https://bugzilla.kernel.org/show_bug.cgi?id=47741.
>
> This happens because thaw_bdev() fails to return -EINVAL in the
> non-frozen case, so fix it so that do_one_thaw() can recognize this case
> and quit from looping. I checked that none of the other thaw_bdev()
> callers check the return value.
>
> The regression was introduced in commit 4504230a7156 ("freeze_bdev: grab
> active reference to frozen superblocks").
>
> Reviewed-by: Chris Mason <clm@fb.com>
> Signed-off-by: Charles Gong <cggong@fb.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
(even magic should be finite...)
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2016-08-05 20:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 23:11 [PATCH] Fix sysrq emergency thaw Charles Gong
2016-08-05 20:14 ` Pavel Machek [this message]
[not found] <5823da614460b8c40809e6e0a6de172a9c4f4611.1468015143.git.cggong@fb.com>
2016-07-19 12:15 ` Chris Mason
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