Thank you for the reply. The box from last night is down and awaiting remote
hands I am afraid.
What I did today, was compile from Linus' git tree and force load on another
machine resulting in:
Aug 18 09:32:18 dload05 kernel: [ 268.336887] BUG: unable to handle kernel
NULL pointer dereference at 0000000000000040
Aug 18 09:32:18 dload05 kernel: [ 268.337070] IP: [<ffffffffa02cfda5>]
fscache_object_slow_work_execute+0x755/0xb70 [fscache]
Aug 18 09:32:18 dload05 kernel: [ 268.337214] PGD 377ba067 PUD 77ede067 PMD
0
Aug 18 09:32:18 dload05 kernel: [ 268.337399] Oops: 0002 [#1] SMP
Aug 18 09:32:18 dload05 kernel: [ 268.337541] last sysfs file:
/sys/kernel/uevent_seqnum
Aug 18 09:32:18 dload05 kernel: [ 268.337609] CPU 0
Aug 18 09:32:18 dload05 kernel: [ 268.337709] Modules linked in: cachefiles
af_packet autofs4 ipv6 nfs lockd fscache nfs_acl auth_rpcgss sunrpc
iptable_filter ip_tables x_tables uhci_hcd usbkbd evdev psmouse serio_raw
pcspkr k8temp button processor i2c_piix4 i2c_core shpchp pci_hotplug ext3
jbd mbcache usbhid sr_mod cdrom hid sd_mod sg tg3 ata_generic libphy
ehci_hcd sata_svw ohci_hcd pata_serverworks pata_acpi libata usbcore
scsi_mod floppy thermal fan thermal_sys fuse
Aug 18 09:32:18 dload05 kernel: [ 268.339993] Pid: 4480, comm: kslowd Not
tainted 2.6.31-rc6-iwin-linus-cachefs #1 H8SSL
Aug 18 09:32:18 dload05 kernel: [ 268.340084] RIP:
0010:[<ffffffffa02cfda5>] [<ffffffffa02cfda5>]
fscache_object_slow_work_execute+0x755/0xb70 [fscache]
Aug 18 09:32:18 dload05 kernel: [ 268.340226] RSP: 0018:ffff880077cbbe60
EFLAGS: 00010246
Aug 18 09:32:18 dload05 kernel: [ 268.340294] RAX: 0000000000000000 RBX:
ffff88007e7ba7f8 RCX: 01000000000000c1
Aug 18 09:32:18 dload05 kernel: [ 268.340366] RDX: ffff88007e7579d0 RSI:
ffffea0001ba9b08 RDI: ffff88007e7ba79c
Aug 18 09:32:18 dload05 kernel: [ 268.340437] RBP: ffff88007e7ba780 R08:
0000000000000000 R09: ffffffff814def00
Aug 18 09:32:18 dload05 kernel: [ 268.340509] R10: 0000000000000000 R11:
0000000000000000 R12: ffff88007e7ba79c
Aug 18 09:32:18 dload05 kernel: [ 268.340581] R13: ffffffff810ad050 R14:
00000000ffffe114 R15: 0000000000000000
Aug 18 09:32:18 dload05 kernel: [ 268.340654] FS: 00007f5bb302a6f0(0000)
GS:ffff880001627000(0000) knlGS:0000000000000000
Aug 18 09:32:18 dload05 kernel: [ 268.340744] CS: 0010 DS: 0018 ES: 0018
CR0: 000000008005003b
Aug 18 09:32:18 dload05 kernel: [ 268.340805] CR2: 0000000000000040 CR3:
0000000074afe000 CR4: 00000000000006f0
Aug 18 09:32:18 dload05 kernel: [ 268.340805] DR0: 0000000000000000 DR1:
0000000000000000 DR2: 0000000000000000
Aug 18 09:32:18 dload05 kernel: [ 268.340805] DR3: 0000000000000000 DR6:
00000000ffff0ff0 DR7: 0000000000000400
Aug 18 09:32:18 dload05 kernel: [ 268.341026] Process kslowd (pid: 4480,
threadinfo ffff880077cba000, task ffff880037b8a080)
Aug 18 09:32:18 dload05 kernel: [ 268.341026] Stack:
Aug 18 09:32:18 dload05 kernel: [ 268.341026] ffff88007e7ba7f8
0000000000000001 0000000000000004 ffffffff810ad050
Aug 18 09:32:18 dload05 kernel: [ 268.341026] <0> 0000000000000000
ffffffff810ad313 0000000000000001 ffff880037b8a080
Aug 18 09:32:18 dload05 kernel: [ 268.341026] <0> ffffffff8105c700
ffff880077cbbea8 ffff880077cbbea8 ffff880077cbbef8
Aug 18 09:32:18 dload05 kernel: [ 268.341026] Call Trace:
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff810ad050>] ?
slow_work_thread+0x0/0x450
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff810ad313>] ?
slow_work_thread+0x2c3/0x450
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff8105c700>] ?
autoremove_wake_function+0x0/0x30
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff810ad050>] ?
slow_work_thread+0x0/0x450
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff8105c596>] ?
kthread+0xa6/0xb0
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff8100cd9a>] ?
child_rip+0xa/0x20
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff8105c4f0>] ?
kthread+0x0/0xb0
Aug 18 09:32:18 dload05 kernel: [ 268.341026] [<ffffffff8100cd90>] ?
child_rip+0x0/0x20
Aug 18 09:32:18 dload05 kernel: [ 268.341026] Code: ff ff 48 8b 45 60 48 83
65 28 fd 4c 8d 65 1c 48 89 ef 48 8b 00 ff 50 18 4c 89 e7 e8 76 67 02 e1 c7
45 00 06 00 00 00 48 8b 45 68 <f0> 0f ba 70 40 01 19 d2 85 d2 74 12 48 8b 7d
68 be 01 00 00 00
Aug 18 09:32:18 dload05 kernel: [ 268.345014] RIP [<ffffffffa02cfda5>]
fscache_object_slow_work_execute+0x755/0xb70 [fscache]
Aug 18 09:32:18 dload05 kernel: [ 268.345014] RSP <ffff880077cbbe60>
Aug 18 09:32:18 dload05 kernel: [ 268.345014] CR2: 0000000000000040
Aug 18 09:32:18 dload05 kernel: [ 268.345603] ---[ end trace
4b1e94ca8e4d77ee ]---
In an attempt to debug I was able to retrieve the below:
This GDB was configured as "x86_64-linux-gnu".
(gdb) file vmlinux
Reading symbols from /usr/local/src/work/vmlinux...done.
(gdb) list *fscache_object_slow_work_execute+0x755
No symbol "fscache_object_slow_work_execute" in current context.
(gdb) list *slow_work_thread+0x0
0xffffffff810ad050 is in slow_work_thread (kernel/slow-work.c:370).
365
366 /*
367 * Worker thread dispatcher
368 */
369 static int slow_work_thread(void *_data)
370 {
371 int vsmax;
372
373 DEFINE_WAIT(wait);
374
(gdb) list *slow_work_thread+0x2c3
0xffffffff810ad313 is in slow_work_thread (kernel/slow-work.c:199).
194 if (!test_and_clear_bit(SLOW_WORK_PENDING, &work->flags))
195 BUG();
196
197 work->ops->execute(work);
198
199 if (very_slow)
200 atomic_dec(&vslow_work_executing_count);
201 clear_bit_unlock(SLOW_WORK_EXECUTING, &work->flags);
202
203 /* if someone tried to enqueue the item whilst we were executing
it,
(gdb) list *autoremove_wake_function+0x0
0xffffffff8105c700 is in autoremove_wake_function (kernel/wait.c:164).
159 spin_unlock_irqrestore(&q->lock, flags);
160 }
161 EXPORT_SYMBOL(abort_exclusive_wait);
162
163 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int
sync, void *key)
164 {
165 int ret = default_wake_function(wait, mode, sync, key);
166
167 if (ret)
168 list_del_init(&wait->task_list);
(gdb) list *kthread+0xa6
0xffffffff8105c596 is in kthread (kernel/kthread.c:80).
75 complete(&create->done);
76 schedule();
77
78 ret = -EINTR;
79 if (!self.should_stop)
80 ret = threadfn(data);
81
82 /* we can't just return, we must preserve "self" on stack */
83 do_exit(ret);
84 }
(gdb) list *child_rip+0xa
0xffffffff8100cd9a is at arch/x86/kernel/entry_64.S:1219.
1214 */
1215 movq %rdi, %rax
1216 movq %rsi, %rdi
1217 call *%rax
1218 # exit
1219 mov %eax, %edi
1220 call do_exit
1221 ud2 # padding for call trace
1222 CFI_ENDPROC
1223 END(child_rip)
(gdb) list *kthread+0x0
0xffffffff8105c4f0 is in kthread (kernel/kthread.c:60).
55 return to_kthread(current)->should_stop;
56 }
57 EXPORT_SYMBOL(kthread_should_stop);
58
59 static int kthread(void *_create)
60 {
61 /* Copy data: it's on kthread's stack */
62 struct kthread_create_info *create = _create;
63 int (*threadfn)(void *data) = create->threadfn;
64 void *data = create->data;
(gdb) list *child_rip+0x0
0xffffffff8100cd90 is at arch/x86/kernel/entry_64.S:1209.
1204 ret
1205 CFI_ENDPROC
1206 END(kernel_thread)
1207
1208 ENTRY(child_rip)
1209 pushq $0 # fake return address
1210 CFI_STARTPROC
1211 /*
1212 * Here we are in the child and the registers are set as they
were
1213 * at kernel_thread() invocation in the parent.
Please let me know what I can do to further help narrow this down.
Thank you,
Joshua
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