Re: ata timeout exceptions

[Damien Le Moal <dlemoal@kernel.org>]

On 12/17/25 08:39, Eyal Lebedinsky wrote:
> Resolved.
> 
> Limiting disk access bandwidth (as suggested by Damien Le Moal <dlemoal@kernel.org>)
> 	# echo 1280 > /sys/block/sdX/queue/max_sectors_kb
> did the trick. No pauses/resets anymore for over a month.

We now have patches queued up to limit max_sectors_kb for devices and
controllers behaving badly. If you send us your device information (hdparm -I)
and controller info (PCI ID of your AHCI adapter), we can add a permanent quirk.

Though we would need to determine if is is the device or the adapter that is
mis-behaving, and also ideally, the command size at which things break.
We had another case with a device breaking above 4MiB commands. A quirk setting
max hw sectors to 8191 sectors solved the issue.

> 
> Setting
> 	# echo 180 >/sys/block/sda/device/timeout
> did not help, only made the pauses longer before the reset.
> 
> Thanks everyone.
> 	Eyal
> 
> On 3/11/25 15:13, Eyal Lebedinsky wrote:
>> I have a sata disk that is probably on its last legs.
>> It is a plain disk (no RAID or such). If it matters, it is an old 8TB Seagate SMA disk.
>> It sees very little activity.
>>
>> Every two hours a small rsync copies a directory into this disk. A few 100s of files are copied each time, a few 10s of GB in total.
>>
>> For the last few weeks it started to log timeout errors (not always) like this:
>>
>>    kernel: ata2.00: exception Emask 0x0 SAct 0x2020 SErr 0x0 action 0x6 frozen
>>    kernel: ata2.00: failed command: WRITE FPDMA QUEUED
>>    kernel: ata2.00: cmd 61/80:28:a0:10:df/00:00:d1:01:00/40 tag 5 ncq dma 65536 out
>>                     res 40/00:00:00:4f:c2/00:00:00:00:00/40 Emask 0x4 (timeout)
>>    kernel: ata2.00: status: { DRDY }
>>    kernel: ata2.00: failed command: WRITE FPDMA QUEUED
>>    kernel: ata2.00: cmd 61/00:68:18:15:30/20:00:20:01:00/40 tag 13 ncq dma 4194304 out
>>                     res 40/00:01:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
>>    kernel: ata2.00: status: { DRDY }
>>    kernel: ata2: hard resetting link
>>    kernel: ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
>>    kernel: ata2.00: configured for UDMA/133
>>    kernel: ata2: EH complete
> 
> [trimmed]
> 


-- 
Damien Le Moal
Western Digital Research