Weird Bug in Linux
by JS
I’m a heavy Linux user, though I’m not a Linux evangelist. For casual computer users Microsoft (if you’re on a budget) or Apple (affordable luxury!) are both better options. That being said, the typical Ubuntu install is actually quite nice and probably worth playing around with if you are a hobbyist. Part of the reason that I feel I can no longer recommend Linux is that my own system has grown unstable, and I have no idea why or what to do about it.
As near as I can tell, some indeterminate amount of time after waking up from a suspend state, the X server on my laptop will crash, freezing even the keyboard input and mouse input and locking me out of my own computer. I’m not even 100% sure that having been in a suspend state is a prerequisite for failure, and the delayed nature of the freeze makes determining any proximal cause extremely difficult.
I’m not really a Linux “expert”, but I am an advanced user whose taken an operating systems class or two and has mastered the art of the command line (the secret sauce — xargs!) as well as several programing languages along the way. But I’m totally stumped by this particular error, and given the deteriorating state of my laptop hardware (the LCD display keeps sprouting new dead pixels, and I’ve had to open the case for repairs more often than I would have liked) I’m not even really sure that this is the kind of problem that can’t be explained by some bad bit of memory somewhere (though memcheck doesn’t detect any problems).
So I’m left with some mysterious log messages (sometimes, and sometimes the crash doesn’t even seem to register in the logs), and a habit of hard rebooting more than I would like. To give you an example of the kind of Greek you’d need to even begin to understand what’s happening, consider this fragment from the log:
Jul 2 19:56:46 stober-laptop kernel: [ 1432.935863] BUG: unable to handle kernel NULL pointer dereference at 00000000000007f8 Jul 2 19:56:46 stober-laptop kernel: [ 1432.935875] IP: [] unmap_page_range+0xa0/0x2a0 Jul 2 19:56:46 stober-laptop kernel: [ 1432.935890] PGD 107544067 PUD 10541e067 PMD 0 Jul 2 19:56:46 stober-laptop kernel: [ 1432.935899] Oops: 0000 [#1] SMP Jul 2 19:56:46 stober-laptop kernel: [ 1432.935906] last sysfs file: /sys/devices/pci0000:00/0000:00:1d.2/usb7/7-0:1.0/bInterfaceClass Jul 2 19:56:46 stober-laptop kernel: [ 1432.935912] CPU 1 Jul 2 19:56:46 stober-laptop kernel: [ 1432.935916] Modules linked in: cryptd aes_x86_64 aes_generic binfmt_misc vmnet ppdev parport_pc vmblock vsock vmci vmmon snd_hda_codec_idt fbcon tileblit font bitblit softcursor vga16fb vgastate joydev arc4 snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq iwl3945 snd_timer iwlcore snd_seq_device mac80211 i915 drm_kms_helper dell_wmi ricoh_mmc psmouse serio_raw sdhci_pci sdhci led_class cfg80211 snd dell_laptop dcdbas drm i2c_algo_bit video output soundcore snd_page_alloc lp parport intel_agp ohci1394 tg3 ieee1394 ahci Jul 2 19:56:46 stober-laptop kernel: [ 1432.936015] Pid: 1087, comm: Xorg Not tainted 2.6.32-23-generic #37-Ubuntu Inspiron 1420 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936021] RIP: 0010:[] [] unmap_page_range+0xa0/0x2a0 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936030] RSP: 0018:ffff8801077d5d48 EFLAGS: 00010206 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936035] RAX: 00007f83220c4000 RBX: 00000000000007f8 RCX: 00007f8321c87000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936040] RDX: 00007fffffffffff RSI: ffff8800a0c15f20 RDI: ffff88002830ea60 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936045] RBP: ffff8801077d5dd8 R08: ffff8801077d5e40 R09: 0000000000000000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936049] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801077d5e40 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936054] R13: ffff8801077d5ea0 R14: 00007f83220c4000 R15: 0000000000000000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936060] FS: 00007f8329ebd700(0000) GS:ffff880028300000(0000) knlGS:0000000000000000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936065] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b Jul 2 19:56:46 stober-laptop kernel: [ 1432.936070] CR2: 00000000000007f8 CR3: 000000011bbe7000 CR4: 00000000000006e0 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936075] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936079] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936085] Process Xorg (pid: 1087, threadinfo ffff8801077d4000, task ffff880103ca96f0) Jul 2 19:56:46 stober-laptop kernel: [ 1432.936089] Stack: Jul 2 19:56:46 stober-laptop kernel: [ 1432.936092] ffff880100000000 ffff8801077d5eb8 0000000000000001 0000000000000000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936100] <0> 00007f83220c3fff 00007f83220c4000 00000000000007f8 ffffffffa00a7d1f Jul 2 19:56:46 stober-laptop kernel: [ 1432.936109] <0> ffff88002830ea60 ffff8801077d5dc8 ffff8800a0c15f20 00007f83220c4000 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936119] Call Trace: Jul 2 19:56:46 stober-laptop kernel: [ 1432.936143] [] ? drm_ioctl+0x13f/0x480 [drm] Jul 2 19:56:46 stober-laptop kernel: [ 1432.936151] [] unmap_vmas+0x178/0x310 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936159] [] unmap_region+0xce/0x170 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936166] [] do_munmap+0x276/0x360 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936175] [] sys_shmdt+0xd0/0x170 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936184] [] system_call_fastpath+0x16/0x1b Jul 2 19:56:46 stober-laptop kernel: [ 1432.936188] Code: 00 80 00 00 00 48 8b 5d a0 48 8d 04 11 48 ba 00 00 00 00 80 ff ff ff 48 21 d0 48 8d 50 ff 48 3b 55 90 48 0f 43 45 98 48 89 45 c8 <48> 8b 3b 48 85 ff 0f 84 b4 01 00 00 48 b8 fb 0f 00 00 00 c0 ff Jul 2 19:56:46 stober-laptop kernel: [ 1432.936262] RIP [] unmap_page_range+0xa0/0x2a0 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936270] RSP Jul 2 19:56:46 stober-laptop kernel: [ 1432.936273] CR2: 00000000000007f8 Jul 2 19:56:46 stober-laptop kernel: [ 1432.936278] ---[ end trace 604847c09536366d ]---
Yeah, I have no idea either.
