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authorJeffrey Carlyle <jeff.carlyle@motorola.com>2010-08-30 19:55:09 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-08-30 19:55:09 +0200
commitedce6820a9fdda85521211cb334a183e34cc455e (patch)
treec2944c0a6e175cd089dde7b808398763ae5c50dd /lib/scatterlist.c
parentb76b4014f9d988d2412b873e4d4c13c7f9afc4e4 (diff)
downloadlinux-2.6.38-lt-ux500-edce6820a9fdda85521211cb334a183e34cc455e.tar.gz
scatterlist: prevent invalid free when alloc fails
When alloc fails, free_table is being called. Depending on the number of bytes requested, we determine if we are going to call _get_free_page() or kmalloc(). When alloc fails, our math is wrong (due to sg_size - 1), and the last buffer is wrongfully assumed to have been allocated by kmalloc. Hence, kfree gets called and a panic occurs. Signed-off-by: Jeffrey Carlyle <jeff.carlyle@motorola.com> Signed-off-by: Olusanya Soyannwo <c23746@motorola.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'lib/scatterlist.c')
-rw-r--r--lib/scatterlist.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index a5ec42868f9..4ceb05d772a 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -248,8 +248,18 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents,
left -= sg_size;
sg = alloc_fn(alloc_size, gfp_mask);
- if (unlikely(!sg))
- return -ENOMEM;
+ if (unlikely(!sg)) {
+ /*
+ * Adjust entry count to reflect that the last
+ * entry of the previous table won't be used for
+ * linkage. Without this, sg_kfree() may get
+ * confused.
+ */
+ if (prv)
+ table->nents = ++table->orig_nents;
+
+ return -ENOMEM;
+ }
sg_init_table(sg, alloc_size);
table->nents = table->orig_nents += sg_size;