Re: Oops in 2.6.19.1

On Sat, Dec 30, 2006 at 04:59:35PM +0000, Alistair John Strachan wrote:
On Thursday 28 December 2006 04:14, Alistair John Strachan wrote:
On Thursday 28 December 2006 04:02, Alistair John Strachan wrote:
On Thursday 28 December 2006 02:41, Zhang, Yanmin wrote:
[snip]

Here's a current decompilation of vmlinux/pipe_poll() from the
running kernel, the addresses have changed slightly. There's no xchg
there either:

Could you reproduce the bug by the new kernel, so we could get the
exact address and instruction of the bug?

It crashed again, but this time with no output (machine locked solid). To
be honest, the disassembly looks right (it's like Chuck said, it's
jumping back half way through an instruction):

c0156f5f: 3b 87 68 01 00 00 cmp 0x168(%edi),%eax

So c0156f60 is 87 68 01 00 00..

This is with the GCC recompile, so it's not a distro problem. It could
still either be GCC 4.x, or a 2.6.19.1 specific bug, but it's serious.
2.6.19 with GCC 3.4.3 is 100% stable.

Looks like a similar crash here:

http://ubuntuforums.org/showthread.php?p=1803389

I've eliminated 2.6.19.1 as the culprit, and also tried toggling "optimize for
size", various debug options. 2.6.19 compiled with GCC 4.1.1 on an Via
Nehemiah C3-2 seems to crash in pipe_poll reliably, within approximately 12
hours.

The machine passes 6 hours of Prime95 (a CPU stability tester), four memtest86
passes, and there are no heat problems.

I have compiled GCC 3.4.6 and compiled 2.6.19 with an identical config using
this compiler (but the same binutils), and will report back if it crashes. My
bet is that it won't, however.

There are occasional reports of problems with kernels compiled with
gcc 4.1 that vanish when using older versions of gcc.

AFAIK, until now noone has ever debugged whether that's a gcc bug,
gcc exposing a kernel bug or gcc exposing a hardware bug.

Comparing your report and [1], it seems that if these are the same
problem, it's not a hardware bug but a gcc or kernel bug.

Cheers,
Alistair.

cu
Adrian

[1] http://bugzilla.kernel.org/show_bug.cgi?id=7176

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Relevant Pages

  • Re: Request for help
    ... My compiler, and the development environment can be downloaded at no ... Gcc 2.95 results differs from gcc 3.4. ... I have reported bugs to GNU several times. ... And if this was a bug, ...
    (comp.lang.c)
  • Re: miscompilation of volatiles?
    ... a bug in that gcc port. ... you must read the documentation that the ... If the compiler documentation says that, ...
    (comp.lang.c)
  • Re: Bye bye Keil 166 and 8051 (??)
    ... I used gcc and two different commercial ... interface bug in gcc. ... The other commercial compiler company never responded to the ...
    (comp.arch.embedded)
  • Re: [patch 00/2] improve .text size on gcc 4.0 and newer compilers
    ... Taking an older compiler from gcc.gnu.org ... OK, but precisely, we don't have any bug free version of gcc anyway. ... kernel has a long history of workaround for gcc bugs. ...
    (Linux-Kernel)
  • Re: [patch] Re: Kernels > 2.6.1-mm3 do not boot. - REALLY SOLVED
    ... > kernel, recompiled without it and all was fine again. ... it was just plain luck that it worked with newer gcc 3.3 and 3.4. ... please merge it if the bug is confirmed to be fixed. ... send the line "unsubscribe linux-kernel" in ...
    (Linux-Kernel)