hpsa: DMAR invalid read

Bug #1813651 reported by Guilherme G. Piccoli on 2019-01-28
14
This bug affects 2 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Medium
Guilherme G. Piccoli
Disco
Medium
Guilherme G. Piccoli

Bug Description

Recently in kernel 4.20-rc1 and newer we observed the following spontaneous issue with hpsa when intel_iommu is enabled:

[ 5173.952022] DMAR: DRHD: handling fault status reg 2
[ 5174.190649] DMAR: [DMA Read] Request device [03:00.0] fault addr eefdd000 [fault reason 06] PTE Read access is not set

There's a commit that touches DMA in hpsa: "scsi: hpsa: switch to generic DMA API"
We've tested with this commit reverted on top of 4.20-rc1 and it reproduces (the trigger is a kernel build). We cannot reproduce in 4.19.

Investigation is ongoing.

Tags: seg Edit Tag help
Guilherme G. Piccoli (gpiccoli) wrote :

Correction: it happens in 4.19 also. I continue with the bisect process.

Terry Rudd (terrykrudd) wrote :

Guilherme, is there going to be further work on this bug?

Guilherme G. Piccoli (gpiccoli) wrote :

Hi Terry, I'm planning to post an update this week.
It seems the problem is related with physical block size adjustments,
after the introduction of the patch: "eb53a3ea3e00 scsi: hpsa: limit transfer length to 1MB, not 512kB"

Without this patch I don't see the issue anymore. But I'm investigating why this patch triggers the issue...

Thanks,

Guilherme

Guilherme G. Piccoli (gpiccoli) wrote :

I've narrowed down the problem for devices in HBA mode; if device is in RAID mode (despite if it's effectively using some raid level or has only 1 disk), it does not reproduce the issue. I'll attach files with outputs from HP RAID utility (accessed in BIOS) for both cases.
I continue the investigation.

Thanks,

Guilherme

Guilherme G. Piccoli (gpiccoli) wrote :
Guilherme G. Piccoli (gpiccoli) wrote :
tags: removed: sts
tags: added: seg
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