WARNING: CPU: 4 PID: 863 at include/drm/drm_crtc.h:1577 drm_helper_choose_encoder_dpms+0x88/0x90()

[Borislav Petkov]

On Wed, Sep 23, 2015 at 04:44:50PM +0200, Daniel Vetter wrote:
> sorry I sprinkled the locking stuff in the wrong places. Still confused
> why the resume side doesn't blow up anywhere

But it does:

[   69.394204] BUG: unable to handle kernel NULL pointer dereference at 0000000000000034
[   69.402080] IP: [<ffffffff81321296>] pci_restore_msi_state+0x196/0x240
[   69.408624] PGD 4162b8067 PUD 416581067 PMD 0 
[   69.413122] Oops: 0000 [#1] PREEMPT SMP 
[   69.417101] Modules linked in: tun sha256_ssse3 sha256_generic drbg binfmt_misc ipv6 vfat fat fuse dm_crypt dm_mod kv
m_amd kvm crc32_pclmul aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd amd64_edac_mod edac_mce_amd fa
m15h_power k10temp amdkfd amd_iommu_v2 radeon acpi_cpufreq
[   69.443647] CPU: 4 PID: 814 Comm: kworker/u16:5 Not tainted 4.3.0-rc2+ #3
[   69.450430] Hardware name: To be filled by O.E.M. To be filled by O.E.M./M5A97 EVO R2.0, BIOS 1503 01/16/2013
[   69.460336] Workqueue: events_unbound async_run_entry_fn
[   69.465667] task: ffff88042a255f00 ti: ffff880428a68000 task.ti: ffff880428a68000
[   69.473145] RIP: 0010:[<ffffffff81321296>]  [<ffffffff81321296>] pci_restore_msi_state+0x196/0x240
[   69.482131] RSP: 0018:ffff880428a6bc28  EFLAGS: 00010286
[   69.487436] RAX: 0000000000000000 RBX: ffff88042a308000 RCX: 0000000000000000
[   69.494568] RDX: 0000000000000001 RSI: ffffffff81304448 RDI: ffffffff816c7a1b
[   69.501700] RBP: ffff880428a6bc40 R08: 0000000000000001 R09: 0000000000522000
[   69.508833] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   69.515965] R13: ffff88042a3087b0 R14: ffff88042a308010 R15: ffff88042a308038
[   69.523097] FS:  00007fc91328a700(0000) GS:ffff88042ce00000(0000) knlGS:0000000000000000
[   69.531185] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   69.536931] CR2: 0000000000000034 CR3: 00000004164c7000 CR4: 00000000000406e0
[   69.544061] Stack:
[   69.546073]  0080002c2a3087b0 0000000000000000 ffff88042a308000 ffff880428a6bc78
[   69.553525]  ffffffff8130c141 ffff88042a308098 ffff88042a308000 0000000000000000
[   69.560996]  ffff8804284e77a8 ffffffff81961ef1 ffff880428a6bc88 ffffffff8130c2b8
[   69.568450] Call Trace:
[   69.571044]  [<ffffffff8130c141>] pci_restore_state.part.18+0xf1/0x250
[   69.577706]  [<ffffffff8130c2b8>] pci_restore_state+0x18/0x20
[   69.583591]  [<ffffffff8130f7fc>] pci_pm_restore_noirq+0x4c/0xd0
[   69.589734]  [<ffffffff8130f7b0>] ? pci_pm_freeze_noirq+0xf0/0xf0
[   69.595966]  [<ffffffff8146e847>] dpm_run_callback+0x77/0x2a0
[   69.601850]  [<ffffffff8146eb03>] device_resume_noirq+0x93/0x150
[   69.607994]  [<ffffffff8146ebdd>] async_resume_noirq+0x1d/0x50
[   69.613967]  [<ffffffff81078a06>] async_run_entry_fn+0x46/0xf0
[   69.619939]  [<ffffffff8106f548>] process_one_work+0x1f8/0x640
[   69.625910]  [<ffffffff8106f4a4>] ? process_one_work+0x154/0x640
[   69.632054]  [<ffffffff8106f9db>] worker_thread+0x4b/0x440
[   69.637677]  [<ffffffff8106f990>] ? process_one_work+0x640/0x640
[   69.643822]  [<ffffffff81075e86>] kthread+0xf6/0x110
[   69.648927]  [<ffffffff81075d90>] ? kthread_create_on_node+0x1f0/0x1f0
[   69.655591]  [<ffffffff816c893f>] ret_from_fork+0x3f/0x70
[   69.661128]  [<ffffffff81075d90>] ? kthread_create_on_node+0x1f0/0x1f0
[   69.667794] Code: 66 89 4d ee 0f b7 c9 e8 79 41 fe ff 48 89 df e8 d1 7a ce ff 0f b6 53 4b 8b 73 38 48 8d 4d ee 48 8b 7b 10 83 c2 02 e8 1a 31 fe ff <41> 0f b6 4c 24 34 41 8b 54 24 30 be ff ff ff ff c0 e9 04 83 e1 
[   69.687986] RIP  [<ffffffff81321296>] pci_restore_msi_state+0x196/0x240
[   69.694772]  RSP <ffff880428a6bc28>
[   69.698412] CR2: 0000000000000034
[   69.701879] ---[ end trace 814dd8cc56e427ae ]---

This happens at resume - I caught the output over serial - screen is
dead, it doesn't show anything because it simply locks up/panics.

> ... Oh well. New patch below.

Yep, this one took care of the warning in
drm_helper_choose_encoder_dpms(). Thanks!

Now I need to go decypher that NULL ptr deref above.

-- 
Regards/Gruss,
    Boris.

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