From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Thu, 6 Feb 2014 20:04:28 +0000 (-0800)
Subject: mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq
X-Git-Tag: v3.2.56~109
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ede028efb3747019a6af0d00536f147d27bfae4d;p=pandora-kernel.git

mm: __set_page_dirty uses spin_lock_irqsave instead of spin_lock_irq

commit 227d53b397a32a7614667b3ecaf1d89902fb6c12 upstream.

To use spin_{un}lock_irq is dangerous if caller disabled interrupt.
During aio buffer migration, we have a possibility to see the following
call stack.

aio_migratepage  [disable interrupt]
  migrate_page_copy
    clear_page_dirty_for_io
      set_page_dirty
        __set_page_dirty_buffers
          __set_page_dirty
            spin_lock_irq

This mean, current aio migration is a deadlockable.  spin_lock_irqsave
is a safer alternative and we should use it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: David Rientjes rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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