Re: [BUG] 2.6.23-git18 Kernel oops in sg helpers

From: Jens Axboe
Date: Thu Oct 25 2007 - 01:34:29 EST


On Thu, Oct 25 2007, FUJITA Tomonori wrote:
> On Wed, 24 Oct 2007 21:38:30 +0530
> Kamalesh Babulal <kamalesh@xxxxxxxxxxxxxxxxxx> wrote:
>
> > FUJITA Tomonori wrote:
> > > On Wed, 24 Oct 2007 12:54:36 +0100
> > > Andy Whitcroft <apw@xxxxxxxxxxxx> wrote:
> > >
> > >> On Tue, Oct 23, 2007 at 08:44:20PM +0200, Jens Axboe wrote:
> > >>> On Tue, Oct 23 2007, Kamalesh Babulal wrote:
> > >>>> Hi,
> > >>>>
> > >>>> Kernel oops is triggered while running fsx-linux test, followed by cpu softlock
> > >>>> over the AMD box
> > >>>>
> > >>>> Unable to handle kernel NULL pointer dereference at 0000000000000018 RIP:
> > >>>> [<ffffffff8021f2f6>] gart_map_sg+0x26c/0x406
> > >>>> PGD 10185b067 PUD 10075b067 PMD 0
> > >>>> Oops: 0002 [1] SMP
> > >>>> CPU 3
> > >>>> Modules linked in:
> > >>>> Pid: 18676, comm: fsx-linux Not tainted 2.6.23-git18-autokern1 #1
> > >>>> RIP: 0010:[<ffffffff8021f2f6>] [<ffffffff8021f2f6>] gart_map_sg+0x26c/0x406
> > >>>> RSP: 0000:ffff810181edf948 EFLAGS: 00010002
> > >>> Can you check where gart_map_sg+0x26c is at? Make sure you have
> > >>> CONFIG_DEBUG_INFO defined, then do:
> > >>>
> > >>> $ gdb vmlinux
> > >>> $ l *gart_map_sg+0x26c
> > >> Ok, this problem still seems to be about in 2.6.24-rc1. Here is the gdb
> > >> output from that version, the panic (also below) seems the same:
> > >>
> > >> (gdb) l *gart_map_sg+0x26c
> > >> 0xffffffff8022011e is in gart_map_sg (arch/x86/kernel/pci-gart_64.c:433).
> > >> 428 goto error;
> > >> 429 out++;
> > >> 430 flush_gart();
> > >> 431 if (out < nents) {
> > >> 432 sgmap = sg_next(sgmap);
> > >> 433 sgmap->dma_length = 0;
> > >> 434 }
> > >> 435 return out;
> > >> 436
> > >> 437 error:
> > >>
> > >> So it seems sg_next has returned 0.
> > >
> > > Have you tried this?
> > >
> > > http://marc.info/?l=linux-kernel&m=119317981406073&w=2
> > > -
> > Hi,
> > Thanks, this patch solves the kernel oops.
>
> Thanks for testing!
>
> Jens, here's the proper changelog.

Thanks, applied!

--
Jens Axboe

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