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

[Tejun Heo <htejun@gmail.com>]

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
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