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SubjectRe: 2.6.17-rc1-mm2: badness in 3w_xxxx driver
On Sun, Apr 09, 2006 at 11:32:40AM -0700, Andrew Morton wrote:
> Nick Orlov <bugfixer@list.ru> wrote:
> >
> > The following patch: x86-kmap_atomic-debugging.patch exposed a badness
> > in 3w_xxx driver.
>
> Sweet, thanks.
>
[[ skipped ]]
>
> From: Andrew Morton <akpm@osdl.org>
>
> We must disable local IRQs while holding KM_IRQ0 or KM_IRQ1. Otherwise, an
> IRQ handler could use those kmap slots while this code is using them,
> resulting in memory corruption.
>
> Thanks to Nick Orlov <bugfixer@list.ru> for reporting.
>
> Cc: <linuxraid@amcc.com>
> Cc: James Bottomley <James.Bottomley@SteelEye.com>
> Signed-off-by: Andrew Morton <akpm@osdl.org>
> ---
>
> drivers/scsi/3w-xxxx.c | 3 +++
> 1 files changed, 3 insertions(+)
>
> diff -puN drivers/scsi/3w-xxxx.c~3ware-kmap_atomic-fix drivers/scsi/3w-xxxx.c
> --- devel/drivers/scsi/3w-xxxx.c~3ware-kmap_atomic-fix 2006-04-09 11:28:08.000000000 -0700
> +++ devel-akpm/drivers/scsi/3w-xxxx.c 2006-04-09 11:29:21.000000000 -0700
> @@ -1508,10 +1508,12 @@ static void tw_transfer_internal(TW_Devi
> struct scsi_cmnd *cmd = tw_dev->srb[request_id];
> void *buf;
> unsigned int transfer_len;
> + unsigned long flags = 0;
>
> if (cmd->use_sg) {
> struct scatterlist *sg =
> (struct scatterlist *)cmd->request_buffer;
> + local_irq_save(flags);
> buf = kmap_atomic(sg->page, KM_IRQ0) + sg->offset;
> transfer_len = min(sg->length, len);
> } else {
> @@ -1526,6 +1528,7 @@ static void tw_transfer_internal(TW_Devi
>
> sg = (struct scatterlist *)cmd->request_buffer;
> kunmap_atomic(buf - sg->offset, KM_IRQ0);
> + local_irq_restore(flags);
> }
> }
>
> _

Confirmed, this patch solves the "badness" problem for me.
I still experiencing a weird hangs though (the box just hangs, no
messages on console/syslog, nothing). I'll try to nail it down.

2.6.16-mm2 works like a charm with the same config.
Do you know which patches should I try to revert first?

--
With best wishes,
Nick Orlov.

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