On 5/3/22 23:55, Liam Howlett wrote:
* Heiko Carstens <hca@xxxxxxxxxxxxx> [220503 15:49]:
On Mon, May 02, 2022 at 08:50:04PM +0200, Heiko Carstens wrote:
On Mon, May 02, 2022 at 01:31:00PM +0000, Liam Howlett wrote:
* Heiko Carstens <hca@xxxxxxxxxxxxx> [220502 06:18]:
On Sun, May 01, 2022 at 05:24:12PM -0700, Andrew Morton wrote:
(cc S390 maintainers)
(cc stable & Greg)
...
booting. The last thing I see is:
"[ 4.668916] Spectre V2 mitigation: execute trampolines"
I've bisected back to commit e553f62f10d9 (mm, page_alloc: fix
build_zonerefs_node())
With the this commit, I am unable to boot one out of three times. When
using the previous commit I was not able to get it to hang after trying
10+ times. This is a qemu s390 install with KASAN on and I see no error
messages. I think it's likely it is this patch, but no guaranteed.
...
Liam, could you share your kernel config?
Sure thing. See attached.
So, I can reproduce the hanging system now. However this looks like a
qemu problem on s390, since I can reproduce this only with Qemu+TCG.
Qemu with kvm works without any problems (same if I use z/VM as
hypervisor).
Janosch, Claudio, can you have a look at this please?
So, at least for me this problem also exists with plain v5.17.
Switching off KASAN, or alternatively switching to KASAN_INLINE
"fixes" it for me with Qemu+TCG.
Liam, could you please also try to disable KASAN in your config? With
that I think we can be almost sure this could be some bug in Qemu.
With KASAN, my tree fails 100% of the time (mm-stable + my maple tree
patches)
Without KASAN, it boots 100% of the time.
I think this verifies with you say above?
Thanks,
Liam
I had a short look yesterday and the boot usually hangs in the raid6
code. Disabling vector instructions didn't make a difference but a few
interruptions via GDB solve the problem for some reason.
CCing David and Thomas for TCG
