Re: [9fans] ilock error/kernel panic (Plan9 hates SciAm)

Re: [9fans] ilock error/kernel panic (Plan9 hates SciAm)

[Russ Cox]

> I think this is the same bug that was reported a few months ago.
> Apparently the fix I suggested was not applied.  That fix is to
> remove the following lines from /sys/src/9/port/taslock.c:

I was looking in the wrong place, at an old copy of the kernel.
The fix has been applied, but it's entirely possible you need
to rebuild your kernel.

Russ

Re: [9fans] ilock error/kernel panic (Plan9 hates SciAm)

[John Waters]

Thanks Russ,
I'll try this once I am out of the office (gmt +3 here, what are you
doing up?? :) ) and write back int the problem persists. The build
that I used is probably 2 weeks old.

John

On Sun, Jul 20, 2008 at 11:26 AM, Russ Cox <rsc@swtch.com> wrote:
>> I think this is the same bug that was reported a few months ago.
>> Apparently the fix I suggested was not applied.  That fix is to
>> remove the following lines from /sys/src/9/port/taslock.c:
>
> I was looking in the wrong place, at an old copy of the kernel.
> The fix has been applied, but it's entirely possible you need
> to rebuild your kernel.
>
> Russ
>
>
>

Re: [9fans] ilock error/kernel panic (Plan9 hates SciAm)

[Russ Cox]

> Hello 9fans,
>
> I was fooling around with a fresh install of plan9 on VMWare fusion,
> copying some files via ftpfs from my hypervisor (Leopard) to my Plan 9
> Guest. Everything was fine until I tried to copy my latest copy of
> Scientific American (14.7mb pdf). It was then that I got the
> error/kernel panic shown. For giggles renamed the file from 200808.pdf
> to sciam-august.pdf, with the same results, I also then bzipped the
> file (which only shaved 1 meg off the file size) and again had the
> same result.
>
> I then created a set of test files (using dd) of 256k, 512k, 768k,
> 1mb, 2mb, 4mb, and 8mb in size and proceeded to attempt to copy them
> in the same manner (via ftpfs to glenda's $home using cp). All
> attempts to copy the files (even the 256k) causes a panic.
>
> Interestingly the 9.intro.pdf file (1.3 meg) copied w/o any issues.
> The *.xls files are between 15 and 60kb. (see attacked image (104k).
>
> For those who don't want to look at the image the error reads:
> ilock :: 00 00 00 00 06 02 00 00 60 7e 11 f0 80 b8 3f f0 00 00 00 00
> (and some other stuff)
> panic: corrupt ilock f0049f40 pc=f0117e60 m=0 isilock=0
> panic: corrupt ilock f0049f40 pc=f0117e60 m=0 isilock=0
> dumpstack disabled
> cpu1: exiting
> cpu0: exiting
>
> Any help or advice regarding this issue would be greatly appreciated.
>
>
> Thanks in advance,
> John

I think this is the same bug that was reported a few months ago.
Apparently the fix I suggested was not applied.  That fix is to
remove the following lines from /sys/src/9/port/taslock.c:

		/*
		 * Cannot also check l->pc and l->m here because
		 * they might just not be set yet, or the lock might
		 * even have been let go.
		 */
		if(!l->isilock){
			dumplockmem("ilock:", l);
			panic("corrupt ilock %p pc=%luX m=%p isilock=%d",
				l, l->pc, l->m, l->isilock);
		}

The comment is correct, and also applies to l->isilock.  Nothing
can be safely checked if the lock isn't held; the particular lock in
your panic is fine.

Russ

[9fans] ilock error/kernel panic (Plan9 hates SciAm)

[John Waters]

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Hello 9fans,

I was fooling around with a fresh install of plan9 on VMWare fusion,
copying some files via ftpfs from my hypervisor (Leopard) to my Plan 9
Guest. Everything was fine until I tried to copy my latest copy of
Scientific American (14.7mb pdf). It was then that I got the
error/kernel panic shown. For giggles renamed the file from 200808.pdf
to sciam-august.pdf, with the same results, I also then bzipped the
file (which only shaved 1 meg off the file size) and again had the
same result.

I then created a set of test files (using dd) of 256k, 512k, 768k,
1mb, 2mb, 4mb, and 8mb in size and proceeded to attempt to copy them
in the same manner (via ftpfs to glenda's $home using cp). All
attempts to copy the files (even the 256k) causes a panic.

Interestingly the 9.intro.pdf file (1.3 meg) copied w/o any issues.
The *.xls files are between 15 and 60kb. (see attacked image (104k).

For those who don't want to look at the image the error reads:
ilock :: 00 00 00 00 06 02 00 00 60 7e 11 f0 80 b8 3f f0 00 00 00 00
(and some other stuff)
panic: corrupt ilock f0049f40 pc=f0117e60 m=0 isilock=0
panic: corrupt ilock f0049f40 pc=f0117e60 m=0 isilock=0
dumpstack disabled
cpu1: exiting
cpu0: exiting

Any help or advice regarding this issue would be greatly appreciated.


Thanks in advance,
John

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