Re: [BUG] 2.5.65-mm3 kernel BUG at fs/ext3/super.c:1795!

Alexander Hoogerhuis
2003-03-22T02:44:26Z

Andrew Morton <akpm@digeo.com> writes:

> Alexander Hoogerhuis <alexh@ihatent.com> wrote:
> >
> > Andrew Morton <akpm@digeo.com> writes:
> > >
> > > [SNIP]
> > >
> >
> > Disk I/O on my machine froze up during very light work after a few
> > hours, luckily I had a window open on another machine so I could do a
> > simple capture and save the info:
> >
> > kernel BUG at fs/ext3/super.c:1795!
> > invalid operand: 0000 [#1]
> > CPU: 0
> > EIP: 0060:[<c018b522>] Not tainted VLI
> > EFLAGS: 00010246
> > EIP is at ext3_write_super+0x36/0x94
> > eax: 00000000 ebx: c8834000 ecx: efb5904c edx: efb59000
> > esi: efb59000 edi: c8834000 ebp: c8835ecc esp: c8835ec0
> > ds: 007b es: 007b ss: 0068
> > Process pdflush (pid: 7853, threadinfo=c8834000 task=ed0a5880)
> > Stack: c8835ee4 00000287 efb5904c c8835ee4 c0153148 efb59000 00000077 51eb851f
> > c8835fcc c8835fa4 c0137fd0 c03892fc 007b9f47 007b168f 00000000 00000000
> > c8835ef4 00000000 00000001 00000000 00000001 00000000 00000053 00000000
> > Call Trace:
> > [<c0153148>] sync_supers+0xde/0xea
> > [<c0137fd0>] wb_kupdate+0x68/0x161
> > [<c0118985>] schedule+0x1a4/0x3ac
> > [<c01386e8>] __pdflush+0xdc/0x1d8
> > [<c01387e4>] pdflush+0x0/0x15
> > [<c01387f5>] pdflush+0x11/0x15
> > [<c0137f68>] wb_kupdate+0x0/0x161
> > [<c0108e69>] kernel_thread_helper+0x5/0xb
>
> How on earth did you do that?
>
> sync_supers() does lock_super, then calls ext3_write_super.
>
> ext3_write_super() does a down_trylock() on sb->s_lock and goes BUG
> if it acquired the lock.
>
> So you've effectively done this:
>
> down(&sem);
> if (down_trylock(&sem))
> BUG();
>
> This can only be a random memory scribble, a hardware bug or a
> preempt-related bug in down_trylock().

Heh. My "portable murphy field" if powerful. Honestly, all I did was
to have a few gnome-terminals, an emacs or two, a few mozillas and a
bit more up, same as always, and jut "just happened" (that's what all
kids claim when they break stuff) :)

mvh,
A
--
Alexander Hoogerhuis | alexh@ihatent.com
CCNP - CCDP - MCNE - CCSE | +47 908 21 485
"You have zero privacy anyway. Get over it." --Scott McNealy