From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941149AbcKNDef (ORCPT ); Sun, 13 Nov 2016 22:34:35 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45298 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753343AbcKNCFC (ORCPT ); Sun, 13 Nov 2016 21:05:02 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Rob Clark" , "Vaishali Thakkar" Date: Mon, 14 Nov 2016 00:14:20 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 228/346] drm/msm: fix use of copy_from_user() while holding spinlock In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Rob Clark commit 89f82cbb0d5c0ab768c8d02914188aa2211cd2e3 upstream. Use instead __copy_from_user_inatomic() and fallback to slow-path where we drop and re-aquire the lock in case of fault. Reported-by: Vaishali Thakkar Signed-off-by: Rob Clark Signed-off-by: Ben Hutchings --- drivers/gpu/drm/msm/msm_gem_submit.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -55,6 +55,14 @@ static struct msm_gem_submit *submit_cre return submit; } +static inline unsigned long __must_check +copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) +{ + if (access_ok(VERIFY_READ, from, n)) + return __copy_from_user_inatomic(to, from, n); + return -EFAULT; +} + static int submit_lookup_objects(struct msm_gem_submit *submit, struct drm_msm_gem_submit *args, struct drm_file *file) { @@ -62,6 +70,7 @@ static int submit_lookup_objects(struct int ret = 0; spin_lock(&file->table_lock); + pagefault_disable(); for (i = 0; i < args->nr_bos; i++) { struct drm_msm_gem_submit_bo submit_bo; @@ -70,10 +79,15 @@ static int submit_lookup_objects(struct void __user *userptr = to_user_ptr(args->bos + (i * sizeof(submit_bo))); - ret = copy_from_user(&submit_bo, userptr, sizeof(submit_bo)); - if (ret) { - ret = -EFAULT; - goto out_unlock; + ret = copy_from_user_inatomic(&submit_bo, userptr, sizeof(submit_bo)); + if (unlikely(ret)) { + pagefault_enable(); + spin_unlock(&file->table_lock); + ret = copy_from_user(&submit_bo, userptr, sizeof(submit_bo)); + if (ret) + goto out; + spin_lock(&file->table_lock); + pagefault_disable(); } if (submit_bo.flags & ~MSM_SUBMIT_BO_FLAGS) { @@ -113,9 +127,12 @@ static int submit_lookup_objects(struct } out_unlock: - submit->nr_bos = i; + pagefault_enable(); spin_unlock(&file->table_lock); +out: + submit->nr_bos = i; + return ret; }