Created attachment 101041 [details]
Full dmesg

This might be invalid, as I'm a kernel newbie trying to workaround a host issue with my hacky patch, but it *seems* to be unrelated to that issue. Any pointers would be welcome.

[  133.921546] BUG: unable to handle kernel NULL pointer dereference at 00000020
[  133.922104] IP: [<f80efb94>] drm_pcie_get_speed_cap_mask+0x24/0xc0 [drm]
[  133.922104] *pde = 00000000 
[  133.922104] Oops: 0000 [#1] PREEMPT SMP 
[  133.922104] Modules linked in: radeon(+) ipv6 hwmon drm_kms_helper ttm drm evdev 8250 serial_core sr_mod i2c_piix4 button i2c_algo_bit cdrom psmouse [last unloaded: radeon]
[  133.922104] Pid: 4983, comm: modprobe Not tainted 3.9.0-gentoo #5 Bochs Bochs
[  133.922104] EIP: 0060:[<f80efb94>] EFLAGS: 00010286 CPU: 0
[  133.922104] EIP is at drm_pcie_get_speed_cap_mask+0x24/0xc0 [drm]
[  133.922104] EAX: f6a96000 EBX: f4073c30 ECX: 00000000 EDX: f4073c30
[  133.922104] ESI: 00000000 EDI: f6b5b070 EBP: f4073c24 ESP: f4073c00
[  133.922104]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  133.922104] CR0: 8005003b CR2: 00000020 CR3: 361d8000 CR4: 000006d0
[  133.922104] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  133.922104] DR6: ffff0ff0 DR7: 00000400
[  133.922104] Process modprobe (pid: 4983, ti=f4072000 task=f6b325d0 task.ti=f4072000)
[  133.922104] Stack:
[  133.922104]  f4073c4c f8828415 00000001 f63ca614 00000001 00000000 00000000 f41e0000
[  133.922104]  ffffffff f4073c3c f886e79d 00001000 00000000 f41e0000 f41e0000 f4073c80
[  133.922104]  f886e8c0 00000000 f6b5b070 f4073c68 f8829403 00000001 00000004 00000000
[  133.922104] Call Trace:
[  133.922104]  [<f8828415>] ? radeon_bo_create+0x145/0x180 [radeon]
[  133.922104]  [<f886e79d>] evergreen_pcie_gen2_enable+0x8d/0x1a0 [radeon]
[  133.922104]  [<f886e8c0>] evergreen_startup+0x10/0x1970 [radeon]
[  133.922104]  [<f8829403>] ? radeon_gart_table_vram_alloc+0x53/0x60 [radeon]
[  133.922104]  [<f8853eb9>] ? r600_pcie_gart_init+0x59/0x60 [radeon]
[  133.922104]  [<f887039c>] evergreen_init+0x17c/0x290 [radeon]
[  133.922104]  [<f8813559>] radeon_device_init+0x559/0x610 [radeon]
[  133.922104]  [<f8812180>] ? cail_mc_write+0x20/0x20 [radeon]
[  133.922104]  [<f8814dd8>] radeon_driver_load_kms+0x78/0x120 [radeon]
[  133.922104]  [<f80efd5b>] drm_get_pci_dev+0x12b/0x240 [drm]
[  133.922104]  [<f88120e1>] radeon_pci_probe+0x81/0xa0 [radeon]
[  133.922104]  [<c120efdb>] pci_device_probe+0x7b/0xc0
[  133.922104]  [<c129207c>] driver_probe_device+0x5c/0x1e0
[  133.922104]  [<c120e6da>] ? pci_match_device+0xaa/0xc0
[  133.922104]  [<c1292289>] __driver_attach+0x89/0x90
[  133.922104]  [<c1292200>] ? driver_probe_device+0x1e0/0x1e0
[  133.922104]  [<c1290a82>] bus_for_each_dev+0x42/0x70
[  133.922104]  [<c1291c7c>] driver_attach+0x1c/0x30
[  133.922104]  [<c1292200>] ? driver_probe_device+0x1e0/0x1e0
[  133.922104]  [<c129186c>] bus_add_driver+0xcc/0x220
[  133.922104]  [<c120ee90>] ? pci_dev_put+0x20/0x20
[  133.922104]  [<c1292715>] driver_register+0x65/0x130
[  133.922104]  [<c120f0be>] __pci_register_driver+0x2e/0x40
[  133.922104]  [<f80eff65>] drm_pci_init+0xf5/0x100 [drm]
[  133.922104]  [<f88ba052>] radeon_init+0x52/0x6f [radeon]
[  133.922104]  [<c100113f>] do_one_initcall+0x2f/0x170
[  133.922104]  [<c10d765e>] ? __vunmap+0x6e/0xd0
[  133.922104]  [<f88ba000>] ? 0xf88b9fff
[  133.922104]  [<c1081ce4>] load_module+0x1ad4/0x2050
[  133.922104]  [<c10d5a93>] ? vmap_page_range_noflush+0x103/0x190
[  133.922104]  [<c11f83a0>] ? _copy_from_user+0x30/0x50
[  133.922104]  [<c10822da>] sys_init_module+0x7a/0xa0
[  133.922104]  [<c1397c60>] syscall_call+0x7/0xb
[  133.922104] Code: 90 90 90 90 90 90 90 55 89 e5 83 ec 24 89 5d f8 89 d3 89 75 fc c7 02 00 00 00 00 8b 80 f0 01 00 00 85 c0 74 10 8b 40 08 8b 70 1c <0f> b7 46 20 66 3d 66 11 75 0f b8 ea ff ff ff 8b 5d f8 8b 75 fc
[  133.922104] EIP: [<f80efb94>] drm_pcie_get_speed_cap_mask+0x24/0xc0 [drm] SS:ESP 0068:f4073c00
[  133.922104] CR2: 0000000000000020
[  133.977137] ---[ end trace 71ff26e878f5734b ]---