Hi!
Debian 8 based system. X suddenly froze. Not quite reproducible, I'm afraid.
Pavel
[331445.592203] ftdi_sio 5-2:1.0: device disconnected [331447.063345] r8169 0000:03:00.0 eth0: link up [331447.930260] PM: resume of devices complete after 2860.478 msecs [331447.930312] ftdi_sio 5-2:1.0: FTDI USB Serial Device converter detected [331447.930481] usb 5-2: Detected FT232RL [331447.933092] usb 5-2: FTDI USB Serial Device converter now attached to ttyUSB0 [331447.933809] PM: resume devices took 2.864 seconds [331447.933870] PM: Finishing wakeup. [331447.933871] Restarting tasks ... [331447.933975] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [331447.933981] pci 0000:00:1f.0: BAR 7: [io size 0x0080] has bogus alignment [331447.933986] pci 0000:00:1e.0: PCI bridge to [bus 04] [331447.942242] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [331447.942252] pci 0000:00:1f.0: BAR 7: [io size 0x0080] has bogus alignment [331447.942257] pci 0000:00:1e.0: PCI bridge to [bus 04] [331447.942414] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [331447.942417] pci 0000:00:1f.0: BAR 7: [io size 0x0080] has bogus alignment [331447.942419] pci 0000:00:1e.0: PCI bridge to [bus 04] [331447.942566] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [331447.942568] pci 0000:00:1f.0: BAR 7: [io size 0x0080] has bogus alignment [331447.942571] pci 0000:00:1e.0: PCI bridge to [bus 04] [331447.942714] i915 0000:00:02.0: BAR 6: [??? 0x00000000 flags 0x2] has bogus alignment [331447.942717] pci 0000:00:1f.0: BAR 7: [io size 0x0080] has bogus alignment [331447.942719] pci 0000:00:1e.0: PCI bridge to [bus 04] [331447.943194] done. [339876.723061] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC [339876.723095] Modules linked in: [339876.723106] CPU: 0 PID: 2672 Comm: Xorg Tainted: G W 4.1.0-rc3 #22 [339876.723130] Hardware name: /DG41MJ, BIOS MJG4110H.86A.0006.2009.1223.1155 12/23/2009 [339876.723159] task: ffff8800a8cee050 ti: ffff8800a8cf0000 task.ti: ffff8800a8cf0000 [339876.723183] RIP: 0010:[<ffffffff843f2d50>] [<ffffffff843f2d50>] intel_gtt_insert_sg_entries+0x30/0xa0 [339876.723220] RSP: 0000:ffff8800a8cf3958 EFLAGS: 00213206 [339876.723235] RAX: 000000005a5a5a5a RBX: ffff88012bf36f00 RCX: 0000000000004d1f [339876.723257] RDX: 0000000000010000 RSI: 0000000000004d1f RDI: ffff88008dd7a500 [339876.723278] RBP: ffff8800a8cf3998 R08: 0000000000000000 R09: 0000000004f6d000 [339876.723300] R10: 0000000000000000 R11: 0000000000000000 R12: 5a5a5a5a5a5a0100 [339876.723322] R13: 0000000000004d1f R14: 0000000000010000 R15: 0000000000000000 [339876.723345] FS: 0000000000000000(0000) GS:ffff88013f200000(0063) knlGS:00000000f714d880 [339876.723370] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [339876.723387] CR2: 00000000f72b4d64 CR3: 000000013200f000 CR4: 00000000000406b0 [339876.723409] Stack: [339876.723413] ffff88008dd7a500 0000000000000000 ffff8800a8cf3988 ffff88012bf36f00 [339876.723444] 0000000000000000 0000000000000000 ffff8801378290a8 0000000000000000 [339876.723475] ffff8800a8cf39b8 ffffffff8444aaa4 ffff8800a8cf3a48 ffff88012bf36f00 [339876.723507] Call Trace: [339876.723517] [<ffffffff8444aaa4>] i915_ggtt_bind_vma+0x44/0x70 [339876.723534] [<ffffffff8444c4a6>] i915_vma_bind+0x46/0x460 [339876.723551] [<ffffffff84327335>] ? swiotlb_map_sg_attrs+0x75/0x160 [339876.723571] [<ffffffff8444bbf2>] ? i915_gem_gtt_prepare_object+0x82/0xc0 [339876.723593] [<ffffffff8445354e>] i915_gem_object_do_pin+0x85e/0x9d0 [339876.723612] [<ffffffff8444cde0>] ? i915_gem_request_free+0x40/0x60 [339876.723633] [<ffffffff844536f5>] i915_gem_object_pin+0x35/0x40 [339876.723652] [<ffffffff844454b1>] i915_gem_execbuffer_reserve_vma.isra.19+0x71/0x140 [339876.723676] [<ffffffff8444585c>] i915_gem_execbuffer_reserve+0x2dc/0x310 [339876.724701] [<ffffffff84445f95>] i915_gem_do_execbuffer.isra.25+0x705/0x11b0 [339876.725709] [<ffffffff841142d7>] ? cache_alloc_debugcheck_after.isra.63+0x67/0x2f0 [339876.726019] [<ffffffff84447c71>] ? i915_gem_execbuffer2+0x91/0x2b0 [339876.726019] [<ffffffff84447d21>] i915_gem_execbuffer2+0x141/0x2b0 [339876.726019] [<ffffffff84408370>] drm_ioctl+0x1a0/0x690 [339876.726019] [<ffffffff84437b55>] i915_compat_ioctl+0x45/0x50 [339876.726019] [<ffffffff84166c20>] compat_SyS_ioctl+0xa0/0x1190 [339876.726019] [<ffffffff840a90f6>] ? ktime_get_ts64+0x86/0x150 [339876.726019] [<ffffffff840a556c>] ? posix_ktime_get_ts+0xc/0x10 [339876.726019] [<ffffffff840a556c>] ? posix_ktime_get_ts+0xc/0x10 [339876.726019] [<ffffffff84310203>] ? lockdep_sys_exit_thunk+0x12/0x14 [339876.726019] [<ffffffff84990255>] ia32_do_call+0x13/0x13 [339876.736025] Code: 57 41 56 41 89 d6 41 55 41 89 f5 41 54 53 48 83 ec 18 8b 47 08 48 89 7d c0 4c 8b 27 c7 45 cc 00 00 00 00 85 c0 74 58 0f 1f 40 00 <41> 8b 5c 24 18 c1 eb 0c 85 db 74 2d 45 31 ff 90 48 8b 0d d9 7f [339876.736025] RIP [<ffffffff843f2d50>] intel_gtt_insert_sg_entries+0x30/0xa0 [339876.736025] RSP <ffff8800a8cf3958> [339876.743455] ---[ end trace e8b388331768406b ]--- [339914.594279] Watchdog[5681]: segfault at 0 ip 000000005a738293 sp 00000000f4aeebb0 error 6 in chromium[56565000+61f2000]