From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45795 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934108AbcILRNj (ORCPT ); Mon, 12 Sep 2016 13:13:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vaishali Thakkar , Rob Clark Subject: [PATCH 4.4 161/192] drm/msm: fix use of copy_from_user() while holding spinlock Date: Mon, 12 Sep 2016 19:01:10 +0200 Message-Id: <20160912152205.817291735@linuxfoundation.org> In-Reply-To: <20160912152158.855601725@linuxfoundation.org> References: <20160912152158.855601725@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable 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: Greg Kroah-Hartman --- 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; }