linux-stable/include
Miklos Szeredi 2aa15890f3 mm: prevent concurrent unmap_mapping_range() on the same inode
Michael Leun reported that running parallel opens on a fuse filesystem
can trigger a "kernel BUG at mm/truncate.c:475"

Gurudas Pai reported the same bug on NFS.

The reason is, unmap_mapping_range() is not prepared for more than
one concurrent invocation per inode.  For example:

  thread1: going through a big range, stops in the middle of a vma and
     stores the restart address in vm_truncate_count.

  thread2: comes in with a small (e.g. single page) unmap request on
     the same vma, somewhere before restart_address, finds that the
     vma was already unmapped up to the restart address and happily
     returns without doing anything.

Another scenario would be two big unmap requests, both having to
restart the unmapping and each one setting vm_truncate_count to its
own value.  This could go on forever without any of them being able to
finish.

Truncate and hole punching already serialize with i_mutex.  Other
callers of unmap_mapping_range() do not, and it's difficult to get
i_mutex protection for all callers.  In particular ->d_revalidate(),
which calls invalidate_inode_pages2_range() in fuse, may be called
with or without i_mutex.

This patch adds a new mutex to 'struct address_space' to prevent
running multiple concurrent unmap_mapping_range() on the same mapping.

[ We'll hopefully get rid of all this with the upcoming mm
  preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex
  lockbreak" patch in particular.  But that is for 2.6.39 ]

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Michael Leun <lkml20101129@newton.leun.net>
Reported-by: Gurudas Pai <gurudas.pai@oracle.com>
Tested-by: Gurudas Pai <gurudas.pai@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-02-23 19:52:52 -08:00
..
acpi Merge branch 'acpica' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2011-01-20 16:28:34 -08:00
asm-generic tracing: Replace syscall_meta_data struct array with pointer array 2011-02-03 09:29:06 -05:00
crypto
drm drm/radeon: remove 0x4243 pci id 2011-02-02 12:50:41 +10:00
keys
linux mm: prevent concurrent unmap_mapping_range() on the same inode 2011-02-23 19:52:52 -08:00
math-emu
media [media] v4l: Include linux/videodev2.h in media/v4l2-ctrls.h 2011-01-19 11:52:09 -02:00
mtd
net net_sched: long word align struct qdisc_skb_cb data 2011-02-23 14:17:02 -08:00
pcmcia pcmcia: re-enable Zoomed Video support 2011-02-20 12:47:34 +01:00
rdma RDMA: Update workqueue usage 2011-01-16 21:16:31 -08:00
rxrpc
scsi [SCSI] fix incorrect value of SCSI_MAX_SG_CHAIN_SEGMENTS due to include file ordering 2011-01-24 11:49:34 -06:00
sound ASoC: WM8903: Fix mic detection register definitions 2011-02-13 19:38:06 +00:00
target [SCSI] target: fix use after free detected by SLUB poison 2011-02-12 12:32:41 -06:00
trace tracing: Replace trace_event struct array with pointer array 2011-02-02 21:37:13 -05:00
video
xen Merge branch 'stable/gntdev' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2011-01-13 18:46:48 -08:00
Kbuild