[18/53] mm: vmalloc: check for page allocation failure before vmlist insertion

[Greg KH]

3.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mel Gorman <mgorman@xxxxxxx>

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@xxxxxxx>
Reported-by: Luciano Chavez <lnx1138@xxxxxxxxxxxxxxxxxx>
Tested-by: Luciano Chavez <lnx1138@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 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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