mm: vmalloc: check for page allocation failure before vmlist insertion
authorMel Gorman <mgorman@suse.de>
Thu, 8 Dec 2011 22:34:30 +0000 (14:34 -0800)
committerGreg Kroah-Hartman <gregkh@suse.de>
Wed, 21 Dec 2011 20:58:24 +0000 (12:58 -0800)
commit7e9062c8c8172253a86b3db01e52f8e576306a95
tree9a91d000c1ee7f16794f6855103dbfaf4abda16c
parent2b5650085aa82f04312a9451bbfc45d809580055
mm: vmalloc: check for page allocation failure before vmlist insertion

commit 1368edf0647ac112d8cfa6ce47257dc950c50f5c upstream.

Commit f5252e00 ("mm: avoid null pointer access in vm_struct via
/proc/vmallocinfo") adds newly allocated vm_structs to the vmlist after
it is fully initialised.  Unfortunately, it did not check that
__vmalloc_area_node() successfully populated the area.  In the event of
allocation failure, the vmalloc area is freed but the pointer to freed
memory is inserted into the vmlist leading to a a crash later in
get_vmalloc_info().

This patch adds a check for ____vmalloc_area_node() failure within
__vmalloc_node_range.  It does not use "goto fail" as in the previous
error path as a warning was already displayed by __vmalloc_area_node()
before it called vfree in its failure path.

Credit goes to Luciano Chavez for doing all the real work of identifying
exactly where the problem was.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Luciano Chavez <lnx1138@linux.vnet.ibm.com>
Tested-by: Luciano Chavez <lnx1138@linux.vnet.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-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: Greg Kroah-Hartman <gregkh@suse.de>
mm/vmalloc.c