Messages in this thread | | | From | Joan Bruguera <> | Subject | Re: Wake-up from suspend to RAM broken under `retbleed=stuff` | Date | Sun, 8 Jan 2023 17:11:59 +0000 |
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Hi, sorry that my mail didn't have proper reproduction instructions.
Something important I missed is that on non-affected hardware / QEMU, the kernel parameter must be `retbleed=stuff,force`, as otherwise `retbleed=stuff` is a no-op. In any case, lscpu (or /sys/devices/system/cpu/vulnerabilities/retbleed) should contain "Mitigation: Stuffing".
That's most likely the missing piece as otherwise, all combinations I've tested exhibit this behavior, so I assumed that the problem always reproduces regardless of the config.
More details follow in case it still doesn't reproduce:
The real HW where I found the problem is an HP 250 G6 (Intel i5-7200U), with a desktop environment (Arch Linux, systemd, Sway, etc.), with both: * A recent mainline kernel: commit 0a71553536d270e988580a3daa9fc87535908221 * The latest x86-tip: commit 9c4fb147c3492fd4be1b89c22a4c333308f6f44a The config I use is the following one, which is based on the Arch Linux kernel config (and I leave any new options at their defaults): https://aur.archlinux.org/cgit/aur.git/plain/config?h=linux-mainline&id=20ffc62e08f6b0d48a088bccb6e0c3606b88083a I need to either disable the BPF LSM or apply this patch to boot it: https://lore.kernel.org/lkml/20230107051456.8800-1-joanbrugueram@gmail.com/ I suspend with `systemctl suspend`. Waking up hangs with `retbleed=stuff` and works without it.
For verification I booted Fedora-Cloud-Base-Rawhide-20230107.n.0.x86_64.qcow2 (from https://dl.fedoraproject.org/pub/fedora/linux/development/rawhide/Cloud): qemu-system-x86_64 -nodefaults -enable-kvm -smp 1 -m 1024 -vga std \ -hda Fedora-Cloud-Base-Rawhide-20230107.n.0.x86_64.qcow2 \ -serial stdio -monitor tcp:127.0.0.1:55555,server,nowait I appended `retbleed=stuff,force init=/bin/sh` to the kernel command line, suspended through sysfs and then wrote `system_wakeup` on the QEMU monitor.
For debugging/tracing, I booted the Arch kernel with a busybox initrd: qemu-system-x86_64 -nodefaults -no-reboot -initrd initramfs.gz \ -kernel /boot/vmlinuz-linux-x86tip \ -append "console=ttyS0 loglevel=4 retbleed=stuff,force" \ -serial stdio -monitor tcp:127.0.0.1:55555,server,nowait Suspended through sysfs, enabled singlestep and logs in the QEMU monitor, then did a system_wakeup.
Regards, - Joan
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