2001-11-27 08:06:17

by Marco Berizzi

[permalink] [raw]
Subject: Kernel Panic: too few segs for DMA mapping increase AHC_NSEG

I have upgraded my PC from 768MB RAM to 1GB.
I have recompiled the kernel (2.4.16) for hi mem support (4GB).

I have several file system on the same disk (vfat file system). I have
compiled vfat driver both in the main kernel and as a module. When I
load the module I issue a
'modprobe vfat' and I get this message (only with hi mem kernel
support):

Warning: loading /lib/modules/2.4.16/kernel/fs/vfat/vfat.o will taint
the kernel: no license
I'm using Slackware 8.0. + modutils 2.4.12

Then if I try to copy a file from that filesystem to the root filesystem
I get this error:

Kernel panic: too few segs for DMA mappings increase AHC_NSEG

Kernel panic: too few segs for DMA mappings increase AHC_NSEG

Usually this is the procedure:

root login
modprobe vfat
mount /dev/sda2 /mnt (to mount the fat partition)
cd /usr/src
cp /mnt/linux/kernel/linux-2.2.20.tar.bz2 . (I want to copy kernel
source tarball from the vfat partition to /usr/src)
CRASH..........

Then the system freeze completely, so I press the reset button.
At the startup INIT calls fsck and when the checking is at about 55% it
displays this message:

SCSI1:A:0:0 locking max tag count at 128

then the following startup procedure goes well.

Kernel 2.2.20 works perfectly, both with and without hi mem support.

My MB is ABIT KT7A (bios rev ID 65 11/07/2001). Two 512 MB SDRAM
(takei).
Other HW: AHA 39160, SCSI IBM HD DDYS 18130, Matrox G450.
gcc version 2.95.3

If I compile a kernel without hi mem support all is fine.

Attach contain .config


Attachments:
.config (16.95 kB)

2001-11-27 08:12:25

by Jens Axboe

[permalink] [raw]
Subject: Re: Kernel Panic: too few segs for DMA mapping increase AHC_NSEG

On Tue, Nov 27 2001, Marco Berizzi wrote:
> I have upgraded my PC from 768MB RAM to 1GB.
> I have recompiled the kernel (2.4.16) for hi mem support (4GB).
>
> I have several file system on the same disk (vfat file system). I have
> compiled vfat driver both in the main kernel and as a module. When I
> load the module I issue a
> 'modprobe vfat' and I get this message (only with hi mem kernel
> support):
>
> Warning: loading /lib/modules/2.4.16/kernel/fs/vfat/vfat.o will taint
> the kernel: no license
> I'm using Slackware 8.0. + modutils 2.4.12
>
> Then if I try to copy a file from that filesystem to the root filesystem
> I get this error:
>
> Kernel panic: too few segs for DMA mappings increase AHC_NSEG
>
> Kernel panic: too few segs for DMA mappings increase AHC_NSEG

You still haven't applied the patch I sent? Sending the same report
without this extra added infor 2 or 3 times isn't doing any good, sorry.

--
Jens Axboe

2001-11-27 19:58:58

by Marco Berizzi

[permalink] [raw]
Subject: Re: Kernel Panic: too few segs for DMA mapping increase AHC_NSEG

I have applied your patch against kernel 2.4.16
This was the message:

(Stripping trailing CRs from patch.)
patching file drivers/scsi/aic7xxx/aic7xxx_linux.c
Hunk #1 succeeded at 625 (offset 1 line).
Hunk #3 succeeded at 1714 (offset 1 line).

Then I built a kernel with hi mem support, and vfat driver built as a module.
reboot machine with new kernel.

Root login, modprobe vfat (modutils 2.4.12) and I always get this message:

Warning: loading /lib/modules/2.4.16/kernel/fs/vfat/vfat.o will taint the kernel: no license

Then I try I mount the vfat filesystem:

mount /dev/sda2 /mnt

and when I try to copy a file from the vfat FS to the linux root FS I get this kernel panic message

code: 0f 0b 80 4f 07 80 8b 03 8b 53 2c 83 ca 82 89 50 14 8b 13 8b
too few segs for dma mapping increase ahc-nseg
invalid operand: 0000
cpu: 0
eip: 0010 : [<c017f8b5>] tainted: P
eflags: 000010046
eax: ffffffff ebx: f7ea58f0 ecx: c0214000 edx: 00000000
esi: 00001000 edi: e3062800 ebp: f7ea1b40 esp: c0215e08
ds: 0018 es: 0018 ss: 0018
process swapper (pid:0, stackpage=c0215000)

<0>Kernel panic: Aiee, killing interrupt handler!
in interrupt handler_not syncing.


ebx, edi, ebp values change at every panic.

Hope this help you.

----- Original Message -----
From: "Jens Axboe" <[email protected]>
To: "Marco Berizzi" <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Tuesday, November 27, 2001 9:11 AM
Subject: Re: Kernel Panic: too few segs for DMA mapping increase AHC_NSEG


> On Tue, Nov 27 2001, Marco Berizzi wrote:
> > I have upgraded my PC from 768MB RAM to 1GB.
> > I have recompiled the kernel (2.4.16) for hi mem support (4GB).
> >
> > I have several file system on the same disk (vfat file system). I have
> > compiled vfat driver both in the main kernel and as a module. When I
> > load the module I issue a
> > 'modprobe vfat' and I get this message (only with hi mem kernel
> > support):
> >
> > Warning: loading /lib/modules/2.4.16/kernel/fs/vfat/vfat.o will taint
> > the kernel: no license
> > I'm using Slackware 8.0. + modutils 2.4.12
> >
> > Then if I try to copy a file from that filesystem to the root filesystem
> > I get this error:
> >
> > Kernel panic: too few segs for DMA mappings increase AHC_NSEG
> >
> > Kernel panic: too few segs for DMA mappings increase AHC_NSEG
>
> You still haven't applied the patch I sent? Sending the same report
> without this extra added infor 2 or 3 times isn't doing any good, sorry.
>
> --
> Jens Axboe
>
>

2001-12-13 08:08:06

by Marco Berizzi

[permalink] [raw]
Subject: Re: Kernel Panic: too few segs for DMA mapping increase AHC_NSEG

I'm reporting only a kernel bug.
With Hi mem support enabled, I get a kernel panic trying to copy one
file from a vfat filesystem to ext2.

----- Original Message -----
From: "Albert D. Cahalan" <[email protected]>
To: "Marco Berizzi" <[email protected]>
Sent: Thursday, December 13, 2001 7:44 AM
Subject: Re: Kernel Panic: too few segs for DMA mapping increase
AHC_NSEG


> > I have upgraded my PC from 768MB RAM to 1GB.
>
> Not worth it.
>
> You suffer the overhead of the 4 GB option for only 33% more
> memory. If you'll go past 768 MB, go to 2 GB or 3 GB.
>