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authorYuan Can <yuancan@huawei.com>2022-11-01 06:51:56 +0000
committerMelissa Wen <melissa.srw@gmail.com>2022-11-29 22:08:49 -0100
commit2fe2a8f40c21161ffe7653cc234e7934db5b7cc5 (patch)
treec73116047c10beefc185e3619f5b8f31ba2708eb /drivers/gpu/drm/vkms
parent0d0b368b9d104b437e1f4850ae94bdb9a3601e89 (diff)
drm/vkms: Fix null-ptr-deref in vkms_release()
A null-ptr-deref is triggered when it tries to destroy the workqueue in vkms->output.composer_workq in vkms_release(). KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f] CPU: 5 PID: 17193 Comm: modprobe Not tainted 6.0.0-11331-gd465bff130bf #24 RIP: 0010:destroy_workqueue+0x2f/0x710 ... Call Trace: <TASK> ? vkms_config_debugfs_init+0x50/0x50 [vkms] __devm_drm_dev_alloc+0x15a/0x1c0 [drm] vkms_init+0x245/0x1000 [vkms] do_one_initcall+0xd0/0x4f0 do_init_module+0x1a4/0x680 load_module+0x6249/0x7110 __do_sys_finit_module+0x140/0x200 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The reason is that an OOM happened which triggers the destroy of the workqueue, however, the workqueue is alloced in the later process, thus a null-ptr-deref happened. A simple call graph is shown as below: vkms_init() vkms_create() devm_drm_dev_alloc() __devm_drm_dev_alloc() devm_drm_dev_init() devm_add_action_or_reset() devm_add_action() # an error happened devm_drm_dev_init_release() drm_dev_put() kref_put() drm_dev_release() vkms_release() destroy_workqueue() # null-ptr-deref happened vkms_modeset_init() vkms_output_init() vkms_crtc_init() # where the workqueue get allocated Fix this by checking if composer_workq is NULL before passing it to the destroy_workqueue() in vkms_release(). Fixes: 6c234fe37c57 ("drm/vkms: Implement CRC debugfs API") Signed-off-by: Yuan Can <yuancan@huawei.com> Reviewed-by: Melissa Wen <mwen@igalia.com> Signed-off-by: Melissa Wen <melissa.srw@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221101065156.41584-3-yuancan@huawei.com
Diffstat (limited to 'drivers/gpu/drm/vkms')
-rw-r--r--drivers/gpu/drm/vkms/vkms_drv.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index 8a74f37d5912..69346906ec81 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -57,7 +57,8 @@ static void vkms_release(struct drm_device *dev)
{
struct vkms_device *vkms = drm_device_to_vkms_device(dev);
- destroy_workqueue(vkms->output.composer_workq);
+ if (vkms->output.composer_workq)
+ destroy_workqueue(vkms->output.composer_workq);
}
static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)