Note that sg_mmap_read does not parse the SCSI sense, so the script
might fail for other reasons (some SCSI error) and think its a zero
byte corruption.
If you think an improved version could help (compare results within
the program + parse senses) I can help.
On Fri, Nov 25, 2016 at 10:07 AM, Johannes Thumshirn <jthumshirn@xxxxxxx> wrote:
> On Wed, Nov 23, 2016 at 03:22:04PM -0500, Ewan Milne wrote:
>
> [...]
>
>> ---
>>
>> In other words, this commit made the bad behavior go away in 4.8.
>> Need to look at this in more detail, it doesn't appear as if this patch
>> was intended to fix such a problem.
>>
>> -Ewan
>
> Are you sure it did? I can repropduce copy_to_user() errors with 4.8 as well.
> Using the very same reproducer. On 4.8 it's just harder to trigger and
> doesn't trigger on AHCI as fas as I can telli (maybe I just haven't hit
> it hard enough). I can trigger it on QEMUs SCSI CDROM emulation and hpsa
> though. I cannot however trigger this with a minimal config inside an initrd.
>
>
> Here's my test:
>
> --- 8< ---
> #!/bin/sh
>
> cleanup()
> {
> rm -f expect.txt
> rm -f test.txt
> }
>
> trap cleanup EXIT INT
>
> ./sg_mmap_read -d /dev/sg0 -l 0 | od -x > expect.txt
>
> for i in $(seq 1 5000); do
> ./sg_mmap_read -d /dev/sg0 -l 0 | od -x > test.txt
> diff expect.txt test.txt > /dev/null
> if [ $? -ne 0 ]; then
> echo "FAIL"
> exit 1
> fi
> done
>
> echo "PASS"
>
> --- >8 ---
>
> I added some trace_printk()s to sg.c and try to hunt it down. It'll be good to
> know if anyone of you can reproduce it with the above script as well.
>
> Byte,
> Johannes
> --
> Johannes Thumshirn Storage
> jthumshirn@xxxxxxx +49 911 74053 689
> SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
> GF: Felix Imendörffer, Jane Smithard, Graham Norton
> HRB 21284 (AG Nürnberg)
> Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
