tree 3ab9b9d8f436006926efd7a0671585279d02bc3a
parent 91a0e1edb80a3cdeaa7b8810b65cc7abf6b85af8
author Stephan Mueller <smueller@chronox.de> 1502877384 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1504766139 +0200

crypto: algif_skcipher - only call put_page on referenced and used pages

commit 445a582738de6802669aeed9c33ca406c23c3b1f upstream.

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.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>