mm: vmalloc: check for page allocation failure before vmlist insertion

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.

If accepted, this should be considered a -stable candidate.

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>
Cc: <stable@vger.kernel.org>		[3.1.x+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 050db042b6400402d4ab7aaa2d5a98908779aa5a..51c3554e1c353660a9a790729acd57a66bf3cf68 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1658,6 +1658,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
                goto fail;
 
        addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
+       if (!addr)
+               return NULL;
 
        /*
         * In this function, newly allocated vm_struct is not added