segfault in "blkparse -s"?

segfault in "blkparse -s"?

[M. Edward (Ed) Borasky]

Environment: Gentoo Linux 2.6.25 kernel, AMD Athlon64 X2 dual core, 4 GB 
of RAM, single disk drive sda, reiserfs filesystems.

I started up blktrace with "blktrace -d /dev/sda". Version is
$ blktrace -V
blktrace version 0.99.3

Then I recompiled php to generate some I/O. Then I stopped blktrace and 
ran blkparse. Version is
$ blkparse -V
blkparse version 0.99.3

Both "blkparse sda" and "blkparse -t sda" run fine, but "blkparse -s 
sda" segfaults:

$ blkparse -s sda > blkparse.out
Segmentation fault

It generates partial output before crashing.

I'm planning to try this again under gdb to get a traceback. The Gentoo 
"btrace" package is sys-block/btrace-0.0.20071210202527 -- if this is 
too old, let me know and I'll install something more recent from the 
repositories.

Re: segfault in "blkparse -s"?

[Jens Axboe]

On Sat, May 17 2008, M. Edward (Ed) Borasky wrote:
> Environment: Gentoo Linux 2.6.25 kernel, AMD Athlon64 X2 dual core, 4 GB 
> of RAM, single disk drive sda, reiserfs filesystems.
> 
> I started up blktrace with "blktrace -d /dev/sda". Version is
> $ blktrace -V
> blktrace version 0.99.3
> 
> Then I recompiled php to generate some I/O. Then I stopped blktrace and 
> ran blkparse. Version is
> $ blkparse -V
> blkparse version 0.99.3
> 
> Both "blkparse sda" and "blkparse -t sda" run fine, but "blkparse -s 
> sda" segfaults:
> 
> $ blkparse -s sda > blkparse.out
> Segmentation fault
> 
> It generates partial output before crashing.
> 
> I'm planning to try this again under gdb to get a traceback. The Gentoo 
> "btrace" package is sys-block/btrace-0.0.20071210202527 -- if this is 
> too old, let me know and I'll install something more recent from the 
> repositories.

Could you send me the blktrace output files so that I can reproduce?
You could try self-compiling

http://brick.kernel.dk/snaps/blktrace-git-latest.tar.gz

just to see if it reproduces in current HEAD.

-- 
Jens Axboe

Re: segfault in "blkparse -s"?

[Jens Axboe]

On Sun, May 18 2008, Jens Axboe wrote:
> On Sat, May 17 2008, M. Edward (Ed) Borasky wrote:
> > Environment: Gentoo Linux 2.6.25 kernel, AMD Athlon64 X2 dual core, 4 GB 
> > of RAM, single disk drive sda, reiserfs filesystems.
> > 
> > I started up blktrace with "blktrace -d /dev/sda". Version is
> > $ blktrace -V
> > blktrace version 0.99.3
> > 
> > Then I recompiled php to generate some I/O. Then I stopped blktrace and 
> > ran blkparse. Version is
> > $ blkparse -V
> > blkparse version 0.99.3
> > 
> > Both "blkparse sda" and "blkparse -t sda" run fine, but "blkparse -s 
> > sda" segfaults:
> > 
> > $ blkparse -s sda > blkparse.out
> > Segmentation fault
> > 
> > It generates partial output before crashing.
> > 
> > I'm planning to try this again under gdb to get a traceback. The Gentoo 
> > "btrace" package is sys-block/btrace-0.0.20071210202527 -- if this is 
> > too old, let me know and I'll install something more recent from the 
> > repositories.
> 
> Could you send me the blktrace output files so that I can reproduce?
> You could try self-compiling
> 
> http://brick.kernel.dk/snaps/blktrace-git-latest.tar.gz
> 
> just to see if it reproduces in current HEAD.

This turned out to be missing notify events, for some (as of yet)
undiagnosed reason. I committed a fix to handle those, it's not unlikely
that we COULD miss a notify event and we should cope with that anyway.

-- 
Jens Axboe