radeon: 4.2-rc1 warning when unplugging DVI

[Dave Jones]

I wanted to switch my LCD to a different machine momentarily.
When I plugged the cable back in, this was on the screen..

WARNING: CPU: 1 PID: 209 at kernel/locking/mutex.c:526 __mutex_lock_slowpath+0x322/0x340()
DEBUG_LOCKS_WARN_ON(l->magic != l)
CPU: 1 PID: 209 Comm: kworker/1:3 Not tainted 4.2.0-rc1-gelk-debug+ #1
Workqueue: events radeon_hotplug_work_func [radeon]
 0000000000000009 ffff8800b160bc78 ffffffff9969fad4 0000000080000001
 ffff8800b160bcc8 ffff8800b160bcb8 ffffffff9907689a 00000000000086be
 ffff8800a24182b8 ffff8800a24182c0 ffff8800b086adc0 ffff8800a24182b8
Call Trace:
 [<ffffffff9969fad4>] dump_stack+0x4f/0x7b
 [<ffffffff9907689a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff99076916>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff996a54f2>] __mutex_lock_slowpath+0x322/0x340
 [<ffffffff996a553c>] mutex_lock+0x2c/0x40
 [<ffffffffc02895e6>] radeon_hotplug_work_func+0x26/0x80 [radeon]
 [<ffffffff9908eba7>] process_one_work+0x147/0x420
 [<ffffffff9908f209>] worker_thread+0x69/0x470
 [<ffffffff990a02b3>] ? preempt_count_sub+0xa3/0xf0
 [<ffffffff9908f1a0>] ? rescuer_thread+0x320/0x320
 [<ffffffff990941e7>] kthread+0x107/0x120
 [<ffffffff990940e0>] ? kthread_create_on_node+0x1b0/0x1b0
 [<ffffffff996a7b1f>] ret_from_fork+0x3f/0x70
 [<ffffffff990940e0>] ? kthread_create_on_node+0x1b0/0x1b0
---[ end trace 859b3faf9cb20dd3 ]---
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC 
CPU: 1 PID: 209 Comm: kworker/1:3 Tainted: G        W       4.2.0-rc1-gelk-debug+ #1
Workqueue: events radeon_hotplug_work_func [radeon]
task: ffff8800b086adc0 ti: ffff8800b1608000 task.ti: ffff8800b1608000
RIP: 0010:[<ffffffff9932ffef>]  [<ffffffff9932ffef>] __list_add+0x1f/0xc0
RSP: 0018:ffff8800b160bcf8  EFLAGS: 00010046
RAX: ffff8800a24182d8 RBX: ffff8800b160bd38 RCX: 0000000000000000
RDX: ffff8800a24182d8 RSI: 0000000000000000 RDI: ffff8800b160bd38
RBP: ffff8800b160bd18 R08: 0000000000000000 R09: 0000000000000fcb
R10: 0000000000000353 R11: 00000000ffffffff R12: ffff8800a24182d8
R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff8800bf700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 00000000a25d3000 CR4: 00000000000007e0
Stack:
 ffff8800b160bd18 ffff8800a24182b8 ffff8800a24182c0 ffff8800b086adc0
 ffff8800b160bd88 ffffffff996a5291 ffff8800b160bd58 ffff8800a24182d8
 ffff8800b160bd38 ffff8800b160bd38 1111111111111111 ffff8800b160bd38
Call Trace:
 [<ffffffff996a5291>] __mutex_lock_slowpath+0xc1/0x340
 [<ffffffff996a553c>] mutex_lock+0x2c/0x40
 [<ffffffffc02895e6>] radeon_hotplug_work_func+0x26/0x80 [radeon]
 [<ffffffff9908eba7>] process_one_work+0x147/0x420
 [<ffffffff9908f209>] worker_thread+0x69/0x470
 [<ffffffff990a02b3>] ? preempt_count_sub+0xa3/0xf0
 [<ffffffff9908f1a0>] ? rescuer_thread+0x320/0x320
 [<ffffffff990941e7>] kthread+0x107/0x120
 [<ffffffff990940e0>] ? kthread_create_on_node+0x1b0/0x1b0
 [<ffffffff996a7b1f>] ret_from_fork+0x3f/0x70
 [<ffffffff990940e0>] ? kthread_create_on_node+0x1b0/0x1b0
Code: c3 66 2e 0f 1f 84 00 00 00 00 00 90 55 48 89 e5 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb 48 83 ec 08 4c 8b 42 08 49 39 f0 75 2e <4d> 8b 45 00 4d 39 c4 75 4e 4c 39 e3 74 6b 4c 39 eb 74 66 49 89 


radeon is an RV370.

	Dave