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| author | Jeffrey Carlyle <jeff.carlyle@motorola.com> | 2010-08-30 19:55:09 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2010-08-30 19:55:09 +0200 |
| commit | edce6820a9fdda85521211cb334a183e34cc455e (patch) | |
| tree | c2944c0a6e175cd089dde7b808398763ae5c50dd /lib/scatterlist.c | |
| parent | b76b4014f9d988d2412b873e4d4c13c7f9afc4e4 (diff) | |
| download | lwn-edce6820a9fdda85521211cb334a183e34cc455e.tar.gz lwn-edce6820a9fdda85521211cb334a183e34cc455e.zip | |
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.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c index a5ec42868f99..4ceb05d772ae 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; |