Re: 2.6.14: Oops on suspend after on-the-fly switch to anticipatory i/o scheduler - PowerBook5,4

Tejun Heo
2005-10-30T13:43:51Z

Tejun Heo wrote:
> Hello, Paul.
>
> Paul Collins wrote:
>
>> I boot with elevator=cfq (wanted to try the ionice stuff, never got
>> around to it). Having decided to go back to the anticipatory
>> scheduler, I did the following:
>>
>> # echo anticipatory > /sys/block/hda/queue/scheduler
>> # echo anticipatory > /sys/block/hdc/queue/scheduler
>>
>> A while later I did 'sudo snooze', which produced the Oops below.
>>
>> Booting with elevator=as and then changing to cfq, sleep works fine.
>> But if I resume and change back to anticipatory I get a similar Oops
>> on the next 'sudo snooze'.
>>
>>
>> Oops: kernel access of bad area, sig: 11 [#1]
>> NIP: C01E1948 LR: C01D6A60 SP: EFBC5C20 REGS: efbc5b70 TRAP: 0300
>> Not tainted
>> MSR: 00001032 EE: 0 PR: 0 FP: 0 ME: 1 IR/DR: 11
>> DAR: 00000020, DSISR: 40000000
>> TASK = efb012c0[1213] 'pmud' THREAD: efbc4000
>> Last syscall: 54 GPR00: 00080000 EFBC5C20 EFB012C0 EFE9E044
>> EFBC5CE8 00000002 00000000 C03B0000 GPR08: C046E5D8 00000000
>> C03B47C8 E6A58360 22042422 1001E4DC 10010000 10000000 GPR16:
>> 10000000 10000000 10000000 7FE4EB40 10000000 10000000 10010000
>> C0400000 GPR24: C0380000 00000002 00000002 C046E0C0 00000000
>> 00000002 00000000 EFBC5CE8 NIP [c01e1948] as_insert_request+0xa8/0x6b0
>> LR [c01d6a60] __elv_add_request+0xa0/0x100
>> Call trace:
>> [c01d6a60] __elv_add_request+0xa0/0x100
>> [c01ffb84] ide_do_drive_cmd+0xb4/0x190
>> [c01fc1c0] generic_ide_suspend+0x80/0xa0
>> [c01d4574] suspend_device+0x104/0x160
>> [c01d47c0] device_suspend+0x120/0x330
>> [c03f3b50] pmac_suspend_devices+0x50/0x1b0
>> [c03f4294] pmu_ioctl+0x344/0x9b0
>> [c0082aa4] do_ioctl+0x84/0x90
>> [c0082b3c] vfs_ioctl+0x8c/0x460
>> [c0082f50] sys_ioctl+0x40/0x80
>> [c0004850] ret_from_syscall+0x0/0x4c
>>
>
> Can you please post assembly of as_insert_request? You can get this by
> doing 'objdump -d drivers/block/as-iosched.o | less' and copy & pasting
> as_insert_request part.
>
> I'm also trying to reproduce the oops but haven't succeeded yet. Does
> the oops occur only if the disk is loaded while switching scheduler /
> snoozing or does it happen regardless of disk load?
>
> And one more thing. Can you please try the following program and see if
> it causes the oops? The program simply writes 3, sleeps one second and
> then writes 0. When redirected to the disk's power/state sysfs node, it
> will make the disk sleep for 1 second and then wake it up.
>
> #include <stdio.h>
> #include <stdlib.h>
>
> int main(int argc, char **argv)
> {
> int level = 3;
> if (argc > 1)
> level = atoi(argv[1]);
> setvbuf(stdout, NULL, _IONBF, 0);
> printf("%d", level);
> sleep(1);
> printf("0");
> return 0;
> }
>
> After compiling, do the following.
>
> ./a.out > /sys/block/hd?/device/power/state
>
> Thanks. :-)
>

Oh.. Never mind. Jens seems to know how to fix it. :-)

--
tejun