[PATCH 1/2] drm/drv: Fix potential memory leak in drm_dev_init()

[Shang XiaoJing]

drm_dev_init() will add drm_dev_init_release() as a callback. When
drmm_add_action() failed, the release function won't be added. As the
result, the ref cnt added by device_get() in drm_dev_init() won't be put
by drm_dev_init_release(), which leads to the memleak. Use
drmm_add_action_or_reset() instead of drmm_add_action() to prevent
memleak.

unreferenced object 0xffff88810bc0c800 (size 2048):
  comm "modprobe", pid 8322, jiffies 4305809845 (age 15.292s)
  hex dump (first 32 bytes):
    e8 cc c0 0b 81 88 ff ff ff ff ff ff 00 00 00 00  ................
    20 24 3c 0c 81 88 ff ff 18 c8 c0 0b 81 88 ff ff   $<.............
  backtrace:
    [<000000007251f72d>] __kmalloc+0x4b/0x1c0
    [<0000000045f21f26>] platform_device_alloc+0x2d/0xe0
    [<000000004452a479>] platform_device_register_full+0x24/0x1c0
    [<0000000089f4ea61>] 0xffffffffa0736051
    [<00000000235b2441>] do_one_initcall+0x7a/0x380
    [<0000000001a4a177>] do_init_module+0x5c/0x230
    [<000000002bf8a8e2>] load_module+0x227d/0x2420
    [<00000000637d6d0a>] __do_sys_finit_module+0xd5/0x140
    [<00000000c99fc324>] do_syscall_64+0x3f/0x90
    [<000000004d85aa77>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 2cbf7fc6718b ("drm: Use drmm_ for drm_dev_init cleanup")
Signed-off-by: Shang XiaoJing <shangxiaojing at huawei.com>
---
 drivers/gpu/drm/drm_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index e3a1243dd2ae..b2c2a5872621 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -616,7 +616,7 @@ static int drm_dev_init(struct drm_device *dev,
 	mutex_init(&dev->clientlist_mutex);
 	mutex_init(&dev->master_mutex);
 
-	ret = drmm_add_action(dev, drm_dev_init_release, NULL);
+	ret = drmm_add_action_or_reset(dev, drm_dev_init_release, NULL);
 	if (ret)
 		return ret;
 
-- 
2.17.1