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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com,
	Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>,
	Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
	dri-devel@lists.freedesktop.org,
	Ezequiel Garcia <ezequiel@collabora.com>
Subject: [PATCH AUTOSEL 5.4 102/175] drm/vkms: Hold gem object while still in-use
Date: Mon,  8 Jun 2020 19:17:35 -0400	[thread overview]
Message-ID: <20200608231848.3366970-102-sashal@kernel.org> (raw)
In-Reply-To: <20200608231848.3366970-1-sashal@kernel.org>

From: Ezequiel Garcia <ezequiel@collabora.com>

[ Upstream commit 0ea2ea42b31abc1141f2fd3911f952a97d401fcb ]

We need to keep the reference to the drm_gem_object
until the last access by vkms_dumb_create.

Therefore, the put the object after it is used.

This fixes a use-after-free issue reported by syzbot.

While here, change vkms_gem_create() symbol to static.

Reported-and-tested-by: syzbot+e3372a2afe1e7ef04bc7@syzkaller.appspotmail.com
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200427214405.13069-1-ezequiel@collabora.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/vkms/vkms_drv.h |  5 -----
 drivers/gpu/drm/vkms/vkms_gem.c | 11 ++++++-----
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 5a95100fa18b..03b05c54722d 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -121,11 +121,6 @@ struct drm_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 				  enum drm_plane_type type, int index);
 
 /* Gem stuff */
-struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
-				       struct drm_file *file,
-				       u32 *handle,
-				       u64 size);
-
 vm_fault_t vkms_gem_fault(struct vm_fault *vmf);
 
 int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
index 6489bfe0a149..8ba8b87d0c99 100644
--- a/drivers/gpu/drm/vkms/vkms_gem.c
+++ b/drivers/gpu/drm/vkms/vkms_gem.c
@@ -95,10 +95,10 @@ vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
 	return ret;
 }
 
-struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
-				       struct drm_file *file,
-				       u32 *handle,
-				       u64 size)
+static struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
+					      struct drm_file *file,
+					      u32 *handle,
+					      u64 size)
 {
 	struct vkms_gem_object *obj;
 	int ret;
@@ -111,7 +111,6 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
 		return ERR_CAST(obj);
 
 	ret = drm_gem_handle_create(file, &obj->gem, handle);
-	drm_gem_object_put_unlocked(&obj->gem);
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -140,6 +139,8 @@ int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
 	args->size = gem_obj->size;
 	args->pitch = pitch;
 
+	drm_gem_object_put_unlocked(gem_obj);
+
 	DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
 
 	return 0;
-- 
2.25.1

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  parent reply	other threads:[~2020-06-08 23:21 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-08 23:15 [PATCH AUTOSEL 5.4 001/175] drm/amdgpu: fix and cleanup amdgpu_gem_object_close v4 Sasha Levin
2020-06-08 23:15 ` [PATCH AUTOSEL 5.4 006/175] drm: bridge: adv7511: Extend list of audio sample rates Sasha Levin
2020-06-08 23:16 ` [PATCH AUTOSEL 5.4 014/175] drm/amdgpu: Init data to avoid oops while reading pp_num_states Sasha Levin
2020-06-08 23:16 ` [PATCH AUTOSEL 5.4 033/175] drm: rcar-du: Set primary plane zpos immutably at initializing Sasha Levin
2020-06-08 23:16 ` [PATCH AUTOSEL 5.4 061/175] staging: android: ion: use vmap instead of vm_map_ram Sasha Levin
2020-06-08 23:17 ` [PATCH AUTOSEL 5.4 071/175] dt-bindings: display: mediatek: control dpi pins mode to avoid leakage Sasha Levin
2020-06-08 23:17 ` [PATCH AUTOSEL 5.4 072/175] drm/mediatek: set dpi pin mode to gpio low to avoid leakage current Sasha Levin
2020-06-08 23:17 ` Sasha Levin [this message]
2020-06-08 23:17 ` [PATCH AUTOSEL 5.4 119/175] drm/mcde: dsi: Fix return value check in mcde_dsi_bind() Sasha Levin
2020-06-08 23:18 ` [PATCH AUTOSEL 5.4 138/175] drm/amd/powerpay: Disable gfxoff when setting manual mode on picasso and raven Sasha Levin
2020-06-08 23:18 ` [PATCH AUTOSEL 5.4 139/175] drm/amdgpu: Sync with VM root BO when switching VM to CPU update mode Sasha Levin

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