[OpenAFS-devel] Re: BUG: unable to handle kernel NULL pointer

[Markus Suvanto]

2013/5/20 Andrew Deason <adeason@sinenomine.net>:
> On Mon, 20 May 2013 20:10:07 +0300
> Markus Suvanto <markus.suvanto@gmail.com> wrote:
>
>> Kernel 3.9.2 and openafs 1.6.3pre2
>>
>>  489.338107] BUG: unable to handle kernel NULL pointer dereference at
>>          (null)
>> [  489.338490] IP: [<          (null)>]           (null)
>> [  489.338692] PGD 37b9b067 PUD 37a0c067 PMD 0
>> [  489.339009] Oops: 0010 [#1] SMP
>> ....
>
> Although I assume this is indeed as easy to reproduce as you say, can
> you post more about what is logged? I assumed you got a stack trace, or
> some kind of indication as to where we are.

Kernel recompiles using CONFIG_KALLSYMS=y
and here is trace.

ay 20 23:36:45 kvm1 kernel: Starting AFS cache scan...found 0
non-empty cache files (0%).
May 20 23:36:45 kvm1 kernel: NET: Registered protocol family 10
May 20 23:37:04 kvm1 kernel: PGD 116a76067 PUD 114fc2067 PMD 0
May 20 23:37:04 kvm1 kernel: Oops: 0010 [#1] SMP
May 20 23:37:04 kvm1 kernel: Modules linked in: ipv6 libafs(PO)
af_packet sr_mod cdrom ata_generic joydev mousedev hid_generic usbhid
pata_acpi crc32c_intel snd_intel8x0 snd_ac97_codec uhci_hcd ac97_bus
ehci_hcd snd_pcm intel_agp snd_page_alloc ppdev evdev psmouse
microcode atkbd snd_timer pcspkr usbcore intel_gtt i2c_piix4 serio_raw
virtio_net firmware_class snd i2c_core usb_common agpgart soundcore
ata_piix parport_pc virtio_balloon rtc_cmos 8250 parport floppy
serial_core processor thermal_sys hwmon button unix btrfs xor
zlib_deflate raid6_pq libcrc32c crc32c ext4 mbcache jbd2 crc16
virtio_pci virtio_blk virtio_ring virtio ahci libahci libata sd_mod
scsi_mod crc_t10dif fbcon font bitblit softcursor fb fbdev
May 20 23:37:04 kvm1 kernel: CPU 4
May 20 23:37:04 kvm1 kernel: Pid: 1599, comm: ld Tainted: P
O 3.9.2 #8 Bochs Bochs
May 20 23:37:04 kvm1 kernel: RIP: 0010:[<0000000000000000>]  [<
  (null)>]           (null)
May 20 23:37:04 kvm1 kernel: RSP: 0018:ffff88011623ba50  EFLAGS: 00010246
May 20 23:37:04 kvm1 kernel: RAX: ffffffff813401c0 RBX:
ffff88011623bad8 RCX: 000000000001461e
May 20 23:37:04 kvm1 kernel: RDX: 0000000000014681 RSI:
ffffea0004375840 RDI: 0000000000000000
May 20 23:37:04 kvm1 kernel: RBP: ffffea0004375880 R08:
ffffea0004375880 R09: 0000000000013746
May 20 23:37:04 kvm1 kernel: R10: 000000000000095e R11:
0000000000000000 R12: ffffea0004375840
May 20 23:37:04 kvm1 kernel: R13: ffff88011716f078 R14:
0000000000000001 R15: 0000000000000000
May 20 23:37:04 kvm1 kernel: FS:  00007f4404ccc700(0000)
GS:ffff88011fc80000(0000) knlGS:0000000000000000
May 20 23:37:04 kvm1 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
May 20 23:37:04 kvm1 kernel: CR2: 0000000000000000 CR3:
00000001191a4000 CR4: 00000000000007e0
May 20 23:37:04 kvm1 kernel: DR0: 0000000000000000 DR1:
0000000000000000 DR2: 0000000000000000
May 20 23:37:04 kvm1 kernel: DR3: 0000000000000000 DR6:
00000000ffff0ff0 DR7: 0000000000000400
May 20 23:37:04 kvm1 kernel: Process ld (pid: 1599, threadinfo
ffff88011623a000, task ffff88011215d280)
May 20 23:37:04 kvm1 kernel: Stack:
May 20 23:37:04 kvm1 kernel:  ffffffffa0807a32 ffff880119a01300
0000000018608b40 ffffc90001478800
May 20 23:37:04 kvm1 kernel:  ffffea0004375880 0000000000001000
ffff880118608b40 ffffc90001478800
May 20 23:37:04 kvm1 kernel:  ffff880119a01300 0000000000000001
ffffffffa08082c8 ffff88011fff8c00
May 20 23:37:04 kvm1 kernel: Call Trace:
May 20 23:37:04 kvm1 kernel:  [<ffffffffa0807a32>] ?
afs_linux_read_cache.isra.20+0x182/0x340 [libafs]
May 20 23:37:04 kvm1 kernel:  [<ffffffffa08082c8>] ?
afs_linux_fillpage+0x6d8/0x9b0 [libafs]
May 20 23:37:04 kvm1 kernel:  [<ffffffffa0796d95>] ?
afs_InitReq+0x85/0xf0 [libafs]
May 20 23:37:04 kvm1 kernel:  [<ffffffffa0809472>] ?
afs_linux_readpage+0x192/0x490 [libafs]
May 20 23:37:04 kvm1 kernel:  [<ffffffff810b1db4>] ?
add_to_page_cache_locked+0x84/0xe0
May 20 23:37:04 kvm1 kernel:  [<ffffffff810b2f64>] ?
generic_file_aio_read+0x204/0x6e0
May 20 23:37:04 kvm1 kernel:  [<ffffffffa0804fa2>] ?
afs_linux_aio_read+0xf2/0x290 [libafs]
May 20 23:37:04 kvm1 kernel:  [<ffffffff810d2e6e>] ? handle_pte_fault+0xae/0x9a0
May 20 23:37:04 kvm1 kernel:  [<ffffffff81100494>] ? do_sync_read+0x94/0xd0
May 20 23:37:04 kvm1 kernel:  [<ffffffff81100c9d>] ? vfs_read+0x16d/0x190
May 20 23:37:04 kvm1 kernel:  [<ffffffff81100e70>] ? sys_read+0x50/0xa0
May 20 23:37:04 kvm1 kernel:  [<ffffffff8132dea9>] ?
system_call_fastpath+0x16/0x1b
May 20 23:37:04 kvm1 kernel: Code:  Bad RIP value.
May 20 23:37:04 kvm1 kernel:  RSP <ffff88011623ba50>
May 20 23:37:04 kvm1 kernel: CR2: 0000000000000000
May 20 23:37:04 kvm1 kernel: ---[ end trace cd4f184e9e79af88 ]---

-Markus






>
> --
> Andrew Deason
> adeason@sinenomine.net
>
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