Messages in this thread | | | Date | Wed, 4 May 2022 09:37:52 +0200 | Subject | Re: [PATCH v8 23/70] mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap() | From | Janosch Frank <> |
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On 5/3/22 23:55, Liam Howlett wrote: > * Heiko Carstens <hca@linux.ibm.com> [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@linux.ibm.com> [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
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