Messages in this thread | | | Date | Wed, 16 Mar 2022 09:51:35 +0000 | From | Jamie Heilman <> | Subject | system locks up with CONFIG_SLS=Y; 5.17.0-rc |
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I've been (somewhat unsuccessfully) trying to bisect a hard lock-up of my workstation that occurs when I'm running 5.17 rc kernels a few seconds after I start a kvm guest instance. There is no output to any log, everything locks up completely, sysrq doesn't even work anymore. As bisection progressed closer and closer to the branch where straight-line-speculation mitigation was enabled, and as bisect landing me between 9cdbeec40968 ("x86/entry_32: Fix segment exceptions") and 3411506550b1 ("x86/csum: Rewrite/optimize csum_partial()") wasn't resulting in clear results (my system definately starts Oopsing and gets so hosed up that I'm forced to reboot, but it isn't quite as dire as sysrq continues to function) I decided to just try a build with CONFIG_SLS disabled, and it turns out that works just fine. Sooo...
This system uses a Intel Core2 Duo E8400 processor. working config (CONFIG_SLS=N) and dmesg at: http://audible.transient.net/~jamie/k/sls.config-5.17.0-rc8 http://audible.transient.net/~jamie/k/sls.dmesg
(I don't think the dmesg of CONFIG_SLS=Y is really any different.)
As far as I know the guest kernel I hand to qemu doesn't really matter, but the gist of my qemu command line is:
qemu-system-x86_64 -m 2048 -name "$NAME" -machine pc,accel=kvm \ -nographic -no-user-config -nodefaults -boot strict=on \ -rtc base=utc -smp 1,sockets=1,cores=1,threads=1 \ -chardev pipe,id=char0,path="$DIR/monitor" \ -chardev pty,id=char1 \ -device isa-serial,chardev=char1 \ -device virtio-blk-pci,drive=blk0,bootindex=1 \ -device virtio-net-pci,netdev=net0,"mac=$IF_MAC" \ -device virtio-rng-pci,rng=rng0,max-bytes=1024,period=3000 \ -drive "id=blk0,file=/dev/S/$NAME,if=none,format=raw,cache=none" \ -mon chardev=char0,id=monitor,mode=control \ -netdev "tap,id=net0,ifname=$NAME,script=no,downscript=no" \ -object rng-random,id=rng0,filename=/dev/random
No clue what additional debugging would help to enable here, if anything. As you can see from the dmesg, I'm using gcc 11.2.0 from Debian unstable, 4:11.2.0-2 to be exact. Let me know what other information would be useful.
-- Jamie Heilman http://audible.transient.net/~jamie/
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