From: Stephan Mueller <smueller@xxxxxxxxxx>
This patch has been added to the v4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 445a582738de6802669aeed9c33ca406c23c3b1f ]
For asynchronous operation, SGs are allocated without a page mapped to
them or with a page that is not used (ref-counted). If the SGL is freed,
the code must only call put_page for an SG if there was a page assigned
and ref-counted in the first place.
This fixes a kernel crash when using io_submit with more than one iocb
using the sendmsg and sendpage (vmsplice/splice) interface.
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
crypto/algif_skcipher.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index c0f03562a145..3734c5591d07 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -94,8 +94,13 @@ static void skcipher_free_async_sgls(struct skcipher_async_req *sreq)
}
sgl = sreq->tsg;
n = sg_nents(sgl);
- for_each_sg(sgl, sg, n, i)
- put_page(sg_page(sg));
+ for_each_sg(sgl, sg, n, i) {
+ struct page *page = sg_page(sg);
+
+ /* some SGs may not have a page mapped */
+ if (page && atomic_read(&page->_count))
+ put_page(page);
+ }
kfree(sreq->tsg);
}
--
2.11.0