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Subject[18/53] mm: vmalloc: check for page allocation failure before vmlist insertion
3.1-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Mel Gorman <mgorman@suse.de>

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 | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1634,6 +1634,8 @@ void *__vmalloc_node_range(unsigned long
return NULL;

addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
+ if (!addr)
+ return NULL;

/*
* In this function, newly allocated vm_struct is not added



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