On 2016-03-31 04:22 PM, Roger H Newell wrote: > On Thu, Mar 31, 2016 at 4:53 PM, <[email protected]> wrote: >> On Thu, 31 Mar 2016 15:46:51 -0230, Roger H Newell said: >> >>> I had a look inside the .config I used to compile this kernel. >>> I think I found the information you're looking for. >>> >>> # CONFIG_KASAN is not set >>> # CONFIG_SLAB is not set >>> CONFIG_SLUB=y >>> # CONFIG_SLOB is not set >> >> Well, that cuts down on the amount of code that needs to be stared at. >> >> I don't suppose we get extra-ordinarily lucky and the system was set up to >> do crash dumps, was it? >> >> I've spent a few more minutes looking at the relevant code, and the more I >> stare at it, the more I understand why we see the same stack trace in varied >> forums going back over a year - it looks like it only craps out if something >> during resume or hotplug or similar processing stomps on memory, and the next >> call to apparmor_file_alloc_security() has to allocate a new slab. >> >> Or more correctly, it only dies with *this* traceback under those conditions. >> If something else is next up to allocate a slab, it gets a different >> traceback. >> >> > > No it wasn't. There is a file > /var/crash/linux-image-4.5.0+.267545.crash. However, its basically the > same output that I pasted from dmesg. I've included it anyway in case > there are some hints in it. > > ProblemType: KernelOops > Annotation: Your system might become unstable now and might need to be > restarted. > Date: Thu Mar 31 12:29:19 2016 > Failure: oops > OopsText: > [961778.803501] BUG: unable to handle kernel NULL pointer dereference > at 0000000000000805 > [961778.809728] IP: [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 > [961778.815943] PGD cea04067 PUD abb59067 PMD 0 > [961778.822149] Oops: 0000 [#3] SMP > [961778.828328] Modules linked in: binfmt_misc snd_hda_codec_realtek > snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel snd_hda_codec > snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event > snd_rawmidi snd_seq snd_seq_device snd_timer edac_mce_amd snd joydev > kvm_amd input_leds edac_core kvm soundcore serio_raw k10temp i2c_piix4 > 8250_fintek asus_atk0110 mac_hid irqbypass parport_pc ppdev lp parport > autofs4 pata_acpi hid_generic usbhid hid amdkfd amd_iommu_v2 radeon > i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt > fb_sys_fops drm psmouse ahci pata_atiixp libahci r8169 mii wmi > [961778.849223] CPU: 2 PID: 23118 Comm: sign-file Tainted: G D > 4.5.0+ #28 > [961778.856339] Hardware name: System manufacturer System Product > Name/M5A78L-M LX PLUS, BIOS 0402 09/20/2011 > [961778.863557] task: ffff88003dbdc100 ti: ffff88009ae3c000 task.ti: > ffff88009ae3c000 > [961778.870811] RIP: 0010:[<ffffffff811e636b>] [<ffffffff811e636b>] > kmem_cache_alloc_trace+0x7b/0x1e0 > [961778.878175] RSP: 0018:ffff88009ae3fc70 EFLAGS: 00010206 > [961778.885522] RAX: 0000000000000000 RBX: 00000000024080c0 RCX: > 000000000bd44541 > [961778.892949] RDX: 000000000bd44540 RSI: 00000000024080c0 RDI: > 0000000000019b20 > [961778.900361] RBP: ffff88009ae3fcb0 R08: ffff88012fc99b20 R09: > ffff88012b003cc0 > [961778.907810] R10: 0000000000000805 R11: fefefefefefefeff R12: > 00000000024080c0 > [961778.915294] R13: ffffffff813736d3 R14: 00007f9b2ac8c040 R15: > ffff88012b003cc0 > [961778.922812] FS: 00007f8546f0a700(0000) GS:ffff88012fc80000(0000) > knlGS:0000000000000000 > [961778.930405] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [961778.937994] CR2: 0000000000000805 CR3: 00000000b9cdc000 CR4: > 00000000000006e0 > [961778.945445] Stack: > [961778.952673] ffffffff81214fef ffff88009ae3fccc 0000000000000002 > ffff880002c28700 > [961778.960013] ffff880002c28700 ffff88009ae3fef4 00007f9b2ac8c040 > ffff88009ae3fde0 > [961778.967372] ffff88009ae3fcc8 ffffffff813736d3 ffffffff81c9fe80 > ffff88009ae3fce8 > [961778.974682] Call Trace: > [961778.981902] [<ffffffff81214fef>] ? lookup_fast+0x16f/0x320 > [961778.989161] [<ffffffff813736d3>] apparmor_file_alloc_security+0x23/0x40 > [961778.996452] [<ffffffff81335b53>] security_file_alloc+0x33/0x50 > [961779.003495] [<ffffffff8120bb6a>] get_empty_filp+0x9a/0x1c0 > [961779.010284] [<ffffffff812176ce>] path_openat+0x2e/0x1400 > [961779.016817] [<ffffffff8121661a>] ? walk_component+0x3a/0x470 > [961779.023241] [<ffffffff811dd0ee>] ? alloc_pages_vma+0xbe/0x240 > [961779.029590] [<ffffffff8121a38e>] do_filp_open+0x7e/0xe0 > [961779.035858] [<ffffffff81196d36>] ? > lru_cache_add_active_or_unevictable+0x36/0xb0 > [961779.042118] [<ffffffff811b9163>] ? handle_mm_fault+0x1253/0x19e0 > [961779.048323] [<ffffffff811e629a>] ? kmem_cache_alloc+0x17a/0x1d0 > [961779.054493] [<ffffffff81227606>] ? __alloc_fd+0x46/0x190 > [961779.060674] [<ffffffff81208984>] do_sys_open+0x124/0x210 > [961779.066821] [<ffffffff81208a8e>] SyS_open+0x1e/0x20 > [961779.072981] [<ffffffff817ec736>] entry_SYSCALL_64_fastpath+0x1e/0xa8 > [961779.079150] Code: 08 65 4c 03 05 3f 3e e2 7e 49 83 78 10 00 4d 8b > 10 0f 84 14 01 00 00 4d 85 d2 0f 84 0b 01 00 00 49 63 41 20 48 8d 4a > 01 49 8b 39 <49> 8b 1c 02 4c 89 d0 65 48 0f c7 0f 0f 94 c0 84 c0 74 bb > 49 63 > [961779.085893] RIP [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 > [961779.092359] RSP <ffff88009ae3fc70> > [961779.098773] CR2: 0000000000000805 > [961779.105231] ---[ end trace e7adb7015192b3a5 ]--- > > Package: linux-image-4.5.0+ (not installed) > SourcePackage: linux > Tags: kernel-oops > Uname: Linux 4.5.0+ x86_64 > > _______________________________________________ > Kernelnewbies mailing list > [email protected] > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > Roger, Are you able to accurately reproduce this error? If so I would very much like to see the output with KASAN enabled to see the actual memory regions being freed/allocated before the NULL deference. Nick
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