linux/include
Mel Gorman 23be7468e8 hugetlb: fix infinite loop in get_futex_key() when backed by huge pages
If a futex key happens to be located within a huge page mapped
MAP_PRIVATE, get_futex_key() can go into an infinite loop waiting for a
page->mapping that will never exist.

See https://bugzilla.redhat.com/show_bug.cgi?id=552257 for more details
about the problem.

This patch makes page->mapping a poisoned value that includes
PAGE_MAPPING_ANON mapped MAP_PRIVATE.  This is enough for futex to
continue but because of PAGE_MAPPING_ANON, the poisoned value is not
dereferenced or used by futex.  No other part of the VM should be
dereferencing the page->mapping of a hugetlbfs page as its page cache is
not on the LRU.

This patch fixes the problem with the test case described in the bugzilla.

[akpm@linux-foundation.org: mel cant spel]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Darren Hart <darren@dvhart.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-24 11:31:25 -07:00
..
acpi acpi: Support IBM SMBus CMI devices 2010-03-24 14:38:37 +01:00
asm-generic dma-mapping: pci: move pci_set_dma_mask and pci_set_consistent_dma_mask to pci-dma-compat.h 2010-03-12 15:52:42 -08:00
crypto
drm Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-04-19 07:27:06 -07:00
keys
linux hugetlb: fix infinite loop in get_futex_key() when backed by huge pages 2010-04-24 11:31:25 -07:00
math-emu
media Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
mtd
net Merge branch 'master' of /home/davem/src/GIT/linux-2.6/ 2010-04-11 02:44:30 -07:00
pcmcia pcmcia: use dev_pm_ops for class pcmcia_socket_class 2010-03-24 11:00:11 +01:00
rdma Merge branch 'misc' into for-next 2010-03-01 23:52:31 -08:00
rxrpc
scsi include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sound Merge branch 'fix/asoc' into for-linus 2010-04-07 09:54:41 +02:00
trace Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 2010-04-09 11:50:29 -07:00
video broadsheetfb: support storing waveform 2010-03-12 15:52:34 -08:00
xen include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kbuild