Re: multiply NULL pointer

Nico Schottelius
2001-08-21T20:18:15Z

> > Hello!
> >
> > Running a p2 400 mhz box with a 3com 3c905, with
> > _very_ heavy nfs traffic and disc io the following NULL
> > pointers were produced. I attached the whole dmesg output.
> > If more informations are needed, I will send them.
> >
> > After every NULL pointer printed on the console
> > I took a new dmesg, so the one with the highest number
> > should be relevant.
> >
>
> Please tell us exactly which kernel you're using. It appears
> to be a flavour of 2.4.7 with ext3, yes?

Yes. plain 2.4.7 + ext3 patch

> Also, please take the very first oops output which occurs
> after a reboot and feed that into
>
> ksymoops -m System.map < oops-trace-file.txt
>
> Make sure you have the correct System.map!

I hope it was the right one (it was the only one left after
I cleaned the system some days ago )

> The fact that your bdflush and kupdate daemons have gone zombie
> suggests that the kernel died in the new buffer flushing code.
> There was a bug fixed in that area late in the 2.4.8-pre series.
>
> >From memory, the bug was a missing test for a null bh in
> fs/buffer.c:sync_old-buffers():
>
> for (;;) {
> struct buffer_head *bh;
>
> spin_lock(&lru_list_lock);
> bh = lru_list[BUF_DIRTY];
> if (!bh || time_before(jiffies, bh->b_flushtime))
> ^^^^^^
>
> You should try 2.4.8.

ok. Will upgrade in the next days.

Nico

ps: ksymoops in another email