2.4.18/2.4.20 filemap.c pmd bug (was Re: Problem with mm in 2.4.19 and 2.4.20)

[Harald Welte <laforge@gnumonks.org>]

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Przemys?aw Maciuszko wrote:

>I have a problem with one news server (feeder) box running INN.
>Under heavy load i get the following error on the console:
>
>filemap.c:2084: bad pmd 2bc001e3
>
>This showed few times during last few days and few times server 'hanged up'
>after this.

I can confirm this problem.  It happens on one of my newsservers as well,
currently at least once per day.  It is a dual PIII 650MHz, 1GB RAM,
200GB spool (scsi hardware raid array attached to adaptec aic7xxx), six
seperate SCSI disks attached to a seperate aic7xxx controller for
overview, running inn-2.3.2.

We've tried  RedHat kernels 2.4.18-3, 2.4.18-17.7, 2.4.20-19.7 and 
2.4.20-19.7bigmem as well as a kernel.org 2.4.20 - all with the same 
problem.

After the filemap.c / pmd_ERROR() printk, the box either hangs (no 
further printout, not that often) or has a stack overflow (most of the 
time):

filemap.c:2258: bad pmd c0003000(00000000000001e3).
do_IRQ: stack overflow: -864
c0252845 fffffca0 206d6564 c2426000 00000000 c0117b20 c0101018 c024bd2c
c2426000 00000018 00000018 00000000 c0117b20 c0101018 c2426470 6f6e0018
40320018 ffffff00 c0117b43 00000010 00000202 7369636e 3e65642e 613c200a
Call Trace:   [<c0117b20>] do_page_fault [kernel] 0x0 (0xc242634c))
[<c0117b20>] do_page_fault [kernel] 0x0 (0xc2426368))
[<c0117b43>] do_page_fault [kernel] 0x23 (0xc2426380))
[<c0117b20>] do_page_fault [kernel] 0x0 (0xc242645c))
[<c0108cc4>] error_code [kernel] 0x34 (0xc2426464))
[<c0117fc5>] do_page_fault [kernel] 0x4a5 (0xc2426498))
[<c0117b20>] do_page_fault [kernel] 0x0 (0xc2426574))
[<c0108cc4>] error_code [kernel] 0x34 (0xc242657c))
[<c0117fc5>] do_page_fault [kernel] 0x4a5 (0xc24265b0))
[<c0117b20>] do_page_fault [kernel] 0x0 (0xc242668c))
[<c0108cc4>] error_code [kernel] 0x34 (0xc2426694))
[<c0117fc5>] do_page_fault [kernel] 0x4a5 (0xc24266c8))
[<c0117b20>] do_page_fault [kernel] 0x0 (0xc24267a4))
[<c0108cc4>] error_code [kernel] 0x34 (0xc24267ac))

The messages are always preceded by a '(scsi0:A:0:0): Locking max tag 
count at 64' message. The scsi device number is changing, so it cannot 
be a single device

>Anyone has an idea what can cause it?

Unfortunately I'm not very familiar with the linux MM subsystem.  But 
since I consider this now as a confirmed bug, maybe some of the other 
lkml folks have an idea what might be going on.

>I'm using Linux Debian on dual PIII 1.1Ghz, 1GB RAM, LVM version 1.0.6
>Qlogic FC 2200F driver version 6.01

We don't use lvm, so the similarities seem to be:  Dual PIII, 
SCSI, INN

--
- Harald Welte <laforge@gnumonks.org>               http://www.gnumonks.org/
============================================================================
Programming is like sex: One mistake and you have to support it your lifetime

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