From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Mueller Subject: [PATCH v2] crypto: only call put_page used pages Date: Sat, 10 Sep 2016 05:48:25 +0200 Message-ID: <2628379.YzI4m1aTC1@positron.chronox.de> References: <2637498.CLV37KecV5@positron.chronox.de> <2555546.QkgIzR2raW@positron.chronox.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-crypto@vger.kernel.org To: herbert@gondor.apana.org.au Return-path: Received: from mail.eperm.de ([89.247.134.16]:47914 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbcIJDsa (ORCPT ); Fri, 9 Sep 2016 23:48:30 -0400 In-Reply-To: <2555546.QkgIzR2raW@positron.chronox.de> Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi Herbert, Changes v2: use sg_page(sg) only once ---8<--- For asynchronous operation, SGs are allocated without a page mapped to them. If the SGL is freed, the code must only call put_page for an SG if there was a page assigned to it in the first place. This fixes a kernel crash when using io_submit with more than one iocb. Signed-off-by: Stephan Mueller --- 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 28556fc..d7acb73 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -86,8 +86,13 @@ 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_ref_count(page)) + put_page(page); + } kfree(sreq->tsg); } -- 2.7.4