I'm testing DMAR support on 2.6.32 on Intel VT-d laptop platforms. It
was pretty stable circa 2.6.31-rc5 (we have dozens of machines running
2.6.31-rc8), but in the last two weeks I've had a bunch of instability
on Linus' tip kernels that looked potentially like IOMMU badness.
Today while running 817b33d38 I got the following (on a Thinkpad X200
I'd replaced the Dell with, just in case it was previously-good hardware
[ 29.450550] EXT4-fs error (device sda1): ext4_lookup: deleted inode referenced: 79
[ 30.022328] DRHD: handling fault status reg 3
[ 30.022328] DMAR:[DMA Write] Request device [00:02.0] fault addr ddae28000
[ 30.022328] DMAR:[fault reason 05] PTE Write access is not set
[ 30.146136] DRHD: handling fault status reg 3
[ 30.248938] DMAR:[DMA Write] Request device [00:02.0] fault addr ddae28000
[ 30.248939] DMAR:[fault reason 05] PTE Write access is not set
I don't know that DMAR is resulting in my repeated filesystem
corruption, but it does seem like a potential cause (and would explain
why I'm seeing this whereas most people aren't, since few people are
using VT-d *and* i915).
I see that the BROKEN_GFX_WA code has been removed; do we actually
believe that the relevant code is working? Could it be corrupting my
AHCI DMAs if not? At the end of the last thread Ted thought that we'd
lost a write of an inode block; this time the symptoms look different,
in that I don't see one inode block representing a significant data
loss (though I'm by no means an expert).
I've attached some useful info, let me know if I missed anything.
I'll try running with BROKEN_GFX_WA turned back on and see if that
improves things at all.