As we may release the last reference, we need to store the device in a local variable in order to unlock afterwards.

[ 60.140768] BUG: unable to handle kernel paging request at 6b6b6b9f [ 60.140973] IP: [<c1536d11>] __mutex_unlock_slowpath+0x5a/0x111 [ 60.141014] *pdpt = 0000000024a54001 *pde = 0000000000000000 [ 60.141014] Oops: 0002 [#1] PREEMPT SMP [ 60.141014] last sysfs file: /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/PNP0C0A:00/power_supply/BAT0/voltage_now [ 60.141014] Modules linked in: uvcvideo ath9k pegasus ath9k_common ath9k_hw hid_egalax ath3k joydev asus_laptop sparse_keymap battery input_polldev [ 60.141014] [ 60.141014] Pid: 771, comm: meego-ux-daemon Not tainted 2.6.37.2-7.1 #1 EXOPC EXOPG06411/EXOPG06411 [ 60.141014] EIP: 0060:[<c1536d11>] EFLAGS: 00010046 CPU: 0 [ 60.141014] EIP is at __mutex_unlock_slowpath+0x5a/0x111 [ 60.141014] EAX: 00000100 EBX: 6b6b6b9b ECX: e9b4a1b0 EDX: e4a4e580 [ 60.141014] ESI: db162558 EDI: 00000246 EBP: e480be50 ESP: e480be44 [ 60.141014] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 [ 60.141014] Process meego-ux-daemon (pid: 771, ti=e480a000 task=e9b4a1b0 task.ti=e480a000) [ 60.141014] Stack: [ 60.141014] e4a4e580 db162558 f5a2f838 e480be58 c1536dd0 e480be68 c125ab1b db162558 [ 60.141014] db1624e0 e480be78 c10ba071 db162558 f760241c e480be94 c10bb0bc 000155fe [ 60.141014] f760241c f5a2f838 f5a2f8c8 00000000 e480bea4 c1037c24 00000000 f5a2f838 [ 60.141014] Call Trace: [ 60.141014] [<c1536dd0>] ? mutex_unlock+0x8/0xa [ 60.141014] [<c125ab1b>] ? drm_gem_vm_close+0x39/0x3d [ 60.141014] [<c10ba071>] ? remove_vma+0x2d/0x58 [ 60.141014] [<c10bb0bc>] ? exit_mmap+0x126/0x13f [ 60.141014] [<c1037c24>] ? mmput+0x37/0x9a [ 60.141014] [<c10d450d>] ? exec_mmap+0x178/0x19c [ 60.141014] [<c1537f85>] ? _raw_spin_unlock+0x1d/0x36 [ 60.141014] [<c10d4eb0>] ? flush_old_exec+0x42/0x75 [ 60.141014] [<c1104442>] ? load_elf_binary+0x32a/0x922 [ 60.141014] [<c10d3f76>] ? search_binary_handler+0x200/0x2ea [ 60.141014] [<c10d3ecf>] ? search_binary_handler+0x159/0x2ea [ 60.141014] [<c1104118>] ? load_elf_binary+0x0/0x922 [ 60.141014] [<c10d56b2>] ? do_execve+0x1ff/0x2e6 [ 60.141014] [<c100970e>] ? sys_execve+0x2d/0x55 [ 60.141014] [<c1002a5a>] ? ptregs_execve+0x12/0x18 [ 60.141014] [<c10029dc>] ? sysenter_do_call+0x12/0x3c [ 60.141014] [<c1530000>] ? init_centaur+0x9c/0x1ba [ 60.141014] Code: c1 00 75 0f ba 38 01 00 00 b8 8c 3a 6c c1 e8 cc 2e b0 ff 9c 58 8d 74 26 00 89 c7 fa 90 8d 74 26 00 e8 d2 b4 b2 ff b8 00 01 00 00 <f0> 66 0f c1 43 04 38 e0 74 07 f3 90 8a 43 04 eb f5 83 3d 64 ef [ 60.141014] EIP: [<c1536d11>] __mutex_unlock_slowpath+0x5a/0x111 SS:ESP 0068:e480be44 [ 60.141014] CR2: 000000006b6b6b9f

Reported-by: Rusty Lynch rusty.lynch@intel.com Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: stable@kernel.org --- drivers/gpu/drm/drm_gem.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 57ce27c..74e4ff5 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -499,11 +499,12 @@ EXPORT_SYMBOL(drm_gem_vm_open); void drm_gem_vm_close(struct vm_area_struct *vma) { struct drm_gem_object *obj = vma->vm_private_data; + struct drm_device *dev = obj->dev;

- mutex_lock(&obj->dev->struct_mutex); + mutex_lock(&dev->struct_mutex); drm_vm_close_locked(vma); drm_gem_object_unreference(obj); - mutex_unlock(&obj->dev->struct_mutex); + mutex_unlock(&dev->struct_mutex); } EXPORT_SYMBOL(drm_gem_vm_close);