I was unable too boot 3.18.0-rc6 because of the following kernel panic in drm_calc_vbltimestamp_from_scanoutpos():

[drm] Initialized drm 1.1.0 20060810 [drm] radeon kernel modesetting enabled. [drm] initializing kernel modesetting (RV100 0x1002:0x515E 0x15D9:0x8080). [drm] register mmio base: 0xC8400000 [drm] register mmio size: 65536 radeon 0000:0b:01.0: VRAM: 128M 0x00000000D0000000 - 0x00000000D7FFFFFF (16M used) radeon 0000:0b:01.0: GTT: 512M 0x00000000B0000000 - 0x00000000CFFFFFFF [drm] Detected VRAM RAM=128M, BAR=128M [drm] RAM width 16bits DDR [TTM] Zone kernel: Available graphics memory: 3829346 kiB [TTM] Zone dma32: Available graphics memory: 2097152 kiB [TTM] Initializing pool allocator [TTM] Initializing DMA pool allocator [drm] radeon: 16M of VRAM memory ready [drm] radeon: 512M of GTT memory ready. [drm] GART: num cpu pages 131072, num gpu pages 131072 [drm] PCI GART of 512M enabled (table at 0x0000000037880000). radeon 0000:0b:01.0: WB disabled radeon 0000:0b:01.0: fence driver on ring 0 use gpu addr 0x00000000b0000000 and cpu addr 0xffff8800bbbfa000 [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [drm] Driver supports precise vblank timestamp query. [drm] radeon: irq initialized. [drm] Loading R100 Microcode radeon 0000:0b:01.0: Direct firmware load for radeon/R100_cp.bin failed with error -2 radeon_cp: Failed to load firmware "radeon/R100_cp.bin" [drm:r100_cp_init] *ERROR* Failed to load firmware! radeon 0000:0b:01.0: failed initializing CP (-2). radeon 0000:0b:01.0: Disabling GPU acceleration [drm] radeon: cp finalized BUG: unable to handle kernel NULL pointer dereference at 000000000000025c IP: [<ffffffff8150423b>] drm_calc_vbltimestamp_from_scanoutpos+0x4b/0x320 PGD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc6-4-default #2649 Hardware name: Supermicro X7DB8/X7DB8, BIOS 6.00 07/26/2006 task: ffff880234da2010 ti: ffff880234da4000 task.ti: ffff880234da4000 RIP: 0010:[<ffffffff8150423b>] [<ffffffff8150423b>] drm_calc_vbltimestamp_from_scanoutpos+0x4b/0x320 RSP: 0000:ffff880234da7918 EFLAGS: 00010086 RAX: ffffffff81557890 RBX: 0000000000000000 RCX: ffff880234da7a48 RDX: ffff880234da79f4 RSI: 0000000000000000 RDI: ffff880232e15000 RBP: ffff880234da79b8 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000000a R11: 0000000000000001 R12: ffff880232dda1c0 R13: ffff880232e1518c R14: 0000000000000292 R15: ffff880232e15000 FS: 0000000000000000(0000) GS:ffff88023fc40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 000000000000025c CR3: 0000000002014000 CR4: 00000000000007e0 Stack: ffff880234da79d8 0000000000000286 ffff880232dcbc00 0000000000002480 ffff880234da7958 0000000000000296 ffff880234da7998 ffffffff8151b51d ffff880234da7a48 0000000032dcbeb0 ffff880232dcbc00 ffff880232dcbc58 Call Trace: [<ffffffff8151b51d>] ? drm_vma_offset_remove+0x1d/0x110 [<ffffffff8152dc98>] radeon_get_vblank_timestamp_kms+0x38/0x60 [<ffffffff8152076a>] ? ttm_bo_release_list+0xba/0x180 [<ffffffff81503751>] drm_get_last_vbltimestamp+0x41/0x70 [<ffffffff81503933>] vblank_disable_and_save+0x73/0x1d0 [<ffffffff81106b2f>] ? try_to_del_timer_sync+0x4f/0x70 [<ffffffff81505245>] drm_vblank_cleanup+0x65/0xa0 [<ffffffff815604fa>] radeon_irq_kms_fini+0x1a/0x70 [<ffffffff8156c07e>] r100_init+0x26e/0x410 [<ffffffff8152ae3e>] radeon_device_init+0x7ae/0xb50 [<ffffffff8152d57f>] radeon_driver_load_kms+0x8f/0x210 [<ffffffff81506965>] drm_dev_register+0xb5/0x110 [<ffffffff8150998f>] drm_get_pci_dev+0x8f/0x200 [<ffffffff815291cd>] radeon_pci_probe+0xad/0xe0 [<ffffffff8141a365>] local_pci_probe+0x45/0xa0 [<ffffffff8141b741>] pci_device_probe+0xd1/0x130 [<ffffffff81633dad>] driver_probe_device+0x12d/0x3e0 [<ffffffff8163413b>] __driver_attach+0x9b/0xa0 [<ffffffff816340a0>] ? __device_attach+0x40/0x40 [<ffffffff81631cd3>] bus_for_each_dev+0x63/0xa0 [<ffffffff8163378e>] driver_attach+0x1e/0x20 [<ffffffff81633390>] bus_add_driver+0x180/0x240 [<ffffffff81634914>] driver_register+0x64/0xf0 [<ffffffff81419cac>] __pci_register_driver+0x4c/0x50 [<ffffffff81509bf5>] drm_pci_init+0xf5/0x120 [<ffffffff821dc871>] ? ttm_init+0x6a/0x6a [<ffffffff821dc908>] radeon_init+0x97/0xb5 [<ffffffff810002fc>] do_one_initcall+0xbc/0x1f0 [<ffffffff810e3278>] ? __wake_up+0x48/0x60 [<ffffffff8218e256>] kernel_init_freeable+0x18a/0x215 [<ffffffff8218d983>] ? initcall_blacklist+0xc0/0xc0 [<ffffffff818a78f0>] ? rest_init+0x80/0x80 [<ffffffff818a78fe>] kernel_init+0xe/0xf0 [<ffffffff818c0c3c>] ret_from_fork+0x7c/0xb0 [<ffffffff818a78f0>] ? rest_init+0x80/0x80 Code: 45 ac 0f 88 a8 01 00 00 3b b7 d0 01 00 00 49 89 ff 0f 83 99 01 00 00 48 8b 47 20 48 8b 80 88 00 00 00 48 85 c0 0f 84 cd 01 00 00 <41> 8b b1 5c 02 00 00 41 8b 89 58 02 00 00 89 75 98 41 8b b1 60 RIP [<ffffffff8150423b>] drm_calc_vbltimestamp_from_scanoutpos+0x4b/0x320 RSP <ffff880234da7918> CR2: 000000000000025c ---[ end trace ad2c0aadf48e2032 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009

It has helped me to add a NULL pointer check that was suggested at http://lists.freedesktop.org/archives/dri-devel/2014-October/070663.html

I am not familiar with the code. But the change looks sane and we need something fast at this stage of 3.18 development.

Suggested-by: Helge Deller deller@gmx.de Signed-off-by: Petr Mladek pmladek@suse.cz Tested-by: Petr Mladek pmladek@suse.cz --- drivers/gpu/drm/radeon/radeon_kms.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c index 8309b11e674d..03586763ee86 100644 --- a/drivers/gpu/drm/radeon/radeon_kms.c +++ b/drivers/gpu/drm/radeon/radeon_kms.c @@ -795,6 +795,8 @@ int radeon_get_vblank_timestamp_kms(struct drm_device *dev, int crtc,

/* Get associated drm_crtc: */ drmcrtc = &rdev->mode_info.crtcs[crtc]->base; + if (!drmcrtc) + return -EINVAL;

/* Helper routine in DRM core does all the work: */ return drm_calc_vbltimestamp_from_scanoutpos(dev, crtc, max_error,