Bug 77661

Last week I filed a bug report for the same hardware and code path, unloading i915.

It had been broken since v3.13-rc1 and it was solved with two commits from master (v3.15-rc8 at the time).

I will spare repeating the same hardware details, you can check them @ https://bugzilla.kernel.org/show_bug.cgi?id=77321

Yesterday I did a go at v3.15 and it fails with a NULL dereference (last time was a WARN_ON) on i915_gem_obj_to_ggtt, matching the same timing of previous bug, although on Gem management instead of display outputs.

Below is the trace and the entire dmesg is @ http://bpaste.net/raw/361794/

Let me know if I can be of further assistance ;)


[ 1907.660322] vga_switcheroo: disabled
[ 1907.660384] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c0
[ 1907.660398] IP: [<ffffffffc01d6f73>] i915_gem_obj_to_ggtt+0x0/0x4a [i915]
[ 1907.660447] PGD 0 
[ 1907.660453] Oops: 0000 [#1] SMP 
[ 1907.660463] Dumping ftrace buffer:
[ 1907.660472]    (ftrace buffer empty)
[ 1907.660477] Modules linked in: btusb ccm brcmsmac brcmutil mac80211 nouveau i915(-) bcma ttm drm_kms_helper [last unloaded: btusb]
[ 1907.660503] CPU: 3 PID: 8540 Comm: rmmod Not tainted 3.15.0-mbp #19
[ 1907.660510] Hardware name: Apple Inc. MacBookPro6,2/Mac-F22586C8, BIOS    MBP61.88Z.0057.B0F.1112091028 12/09/11
[ 1907.660520] task: ffff880243962010 ti: ffff88023d30c000 task.ti: ffff88023d30c000
[ 1907.660528] RIP: 0010:[<ffffffffc01d6f73>]  [<ffffffffc01d6f73>] i915_gem_obj_to_ggtt+0x0/0x4a [i915]
[ 1907.660570] RSP: 0018:ffff88023d30fd20  EFLAGS: 00010246
[ 1907.660576] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88023d30fd28
[ 1907.660583] RDX: 0000000080000000 RSI: ffffffffc01cb788 RDI: 0000000000000000
[ 1907.660590] RBP: ffff88023d30fd48 R08: 0000000000000000 R09: ffff88023d30fd28
[ 1907.660597] R10: ffff88023d30fd00 R11: 0000000000000001 R12: 00000000000006e0
[ 1907.660604] R13: ffff880243802ec0 R14: 00007fffc270af68 R15: 0000000000000000
[ 1907.660612] FS:  00007fa35f4fd700(0000) GS:ffff88024fcc0000(0000) knlGS:0000000000000000
[ 1907.660621] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1907.660627] CR2: 00000000000000c0 CR3: 00000002439b5000 CR4: 00000000000007e0
[ 1907.660634] Stack:
[ 1907.660638]  ffffffffc01d72b5 ffff880242170000 00000000000006e0 ffff880243802ec0
[ 1907.660649]  00007fffc270af68 ffff88023d30fd70 ffffffffc01cbe4c ffff880242170000
[ 1907.660660]  ffff880243a06800 ffff880243a06868 ffff88023d30fd98 ffffffffc021fb7f
[ 1907.660670] Call Trace:
[ 1907.660709]  [<ffffffffc01d72b5>] ? i915_gem_object_ggtt_unpin+0x13/0x76 [i915]
[ 1907.660744]  [<ffffffffc01cbe4c>] i915_gem_context_fini+0xc8/0xd7 [i915]
[ 1907.660802]  [<ffffffffc021fb7f>] i915_driver_unload+0x185/0x278 [i915]
[ 1907.660813]  [<ffffffffab445120>] drm_dev_unregister+0x23/0x93
[ 1907.660821]  [<ffffffffab445254>] drm_put_dev+0x4a/0x55
[ 1907.660846]  [<ffffffffc01b94e1>] i915_pci_remove+0x18/0x1a [i915]
[ 1907.660857]  [<ffffffffab3b9f45>] pci_device_remove+0x40/0x8a
[ 1907.660866]  [<ffffffffab45ce8b>] __device_release_driver+0x84/0xda
[ 1907.660875]  [<ffffffffab45d4b3>] driver_detach+0x85/0xab
[ 1907.660883]  [<ffffffffab45cbcb>] bus_remove_driver+0x64/0x81
[ 1907.660892]  [<ffffffffab45d9e5>] driver_unregister+0x41/0x44
[ 1907.660900]  [<ffffffffab3b9413>] pci_unregister_driver+0x17/0x64
[ 1907.660909]  [<ffffffffab446dc3>] drm_pci_exit+0x40/0x87
[ 1907.660952]  [<ffffffffc0221a62>] i915_exit+0x20/0x150 [i915]
[ 1907.660963]  [<ffffffffab0fece5>] SyS_delete_module+0x13c/0x1c2
[ 1907.660973]  [<ffffffffab7cb98f>] tracesys+0xe1/0xe6
[ 1907.660978] Code: c7 83 c8 29 00 00 12 5b 1d c0 48 c7 83 c0 29 00 00 6c 1a 1d c0 c7 83 d0 29 00 00 02 00 00 00 e8 5b 4b f7 ea 5b 41 5c 41 5d 5d c3 <48> 8b 97 c0 00 00 00 48 8d 87 c0 00 00 00 48 39 c2 75 19 55 be 
[ 1907.661044] RIP  [<ffffffffc01d6f73>] i915_gem_obj_to_ggtt+0x0/0x4a [i915]
[ 1907.661084]  RSP <ffff88023d30fd20>
[ 1907.661088] CR2: 00000000000000c0
[ 1907.661117] ---[ end trace 79c4f4e26cd5edbe ]---