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From: Rob Clark <robdclark@gmail.com>
To: dri-devel@lists.freedesktop.org
Cc: "Daniel Vetter" <daniel@ffwll.ch>,
	"Rob Clark" <robdclark@chromium.org>,
	syzbot+c8ae65286134dd1b800d@syzkaller.appspotmail.com,
	stable@vger.kernel.org, "Daniel Vetter" <daniel.vetter@ffwll.ch>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Eric Anholt" <eric@anholt.net>, "Rob Herring" <robh@kernel.org>,
	"Noralf Trønnes" <noralf@tronnes.org>,
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2 1/2] drm/shmem-helper: Remove errant put in error path
Date: Wed, 30 Nov 2022 10:57:47 -0800	[thread overview]
Message-ID: <20221130185748.357410-2-robdclark@gmail.com> (raw)
In-Reply-To: <20221130185748.357410-1-robdclark@gmail.com>

From: Rob Clark <robdclark@chromium.org>

drm_gem_shmem_mmap() doesn't own this reference, resulting in the GEM
object getting prematurely freed leading to a later use-after-free.

Link: https://syzkaller.appspot.com/bug?extid=c8ae65286134dd1b800d
Reported-by: syzbot+c8ae65286134dd1b800d@syzkaller.appspotmail.com
Fixes: 2194a63a818d ("drm: Add library for shmem backed GEM objects")
Cc: stable@vger.kernel.org
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 35138f8a375c..3b7b71391a4c 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -622,10 +622,8 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct
 	}
 
 	ret = drm_gem_shmem_get_pages(shmem);
-	if (ret) {
-		drm_gem_vm_close(vma);
+	if (ret)
 		return ret;
-	}
 
 	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-- 
2.38.1


  reply	other threads:[~2022-11-30 18:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-30 18:57 [PATCH v2 0/2] drm/shmem-helper: Fix a couple of error path bugs Rob Clark
2022-11-30 18:57 ` Rob Clark [this message]
2022-12-04 20:45   ` [PATCH v2 1/2] drm/shmem-helper: Remove errant put in error path Dmitry Osipenko
2022-12-06 18:09     ` Rob Clark
2022-11-30 18:57 ` [PATCH v2 2/2] drm/shmem-helper: Avoid vm_open error paths Rob Clark

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