Add Dave to CC On 10/28/22 at 01:02pm, ns@xxxxxxxx wrote: > Greetings, > > I've been hitting a bug on my Lenovo ThinkPad T480 where kexecing will > cause EFI mode (if that's the right term for it) to be unconditionally > disabled, even when not using the --noefi option to kexec. > > What I mean by "EFI mode" being disabled, more than just EFI runtime > services, is that basically nothing about the system's EFI is visible > post-kexec. Normally you have a message like this in dmesg when the > system is booted in EFI mode: > > [ 0.000000] efi: EFI v2.70 by EDK II > [ 0.000000] efi: SMBIOS=0x7f98a000 ACPI=0x7fb7e000 ACPI 2.0=0x7fb7e014 > MEMATTR=0x7ec63018 > (obviously not the real firmware of the machine I'm talking about, but I > can also send that if it would be of any help) > > No such message pops up in my dmesg as a result of this bug, & this > causes some fallout like being unable to find the system's DMI > information: > > <6>[ 0.000000] DMI not present or invalid. > > The efivarfs module also fails to load with -ENODEV. > > I've tried also booting with efi=runtime explicitly but it doesn't > change anything. The kernel still does not print the name of the EFI > firmware, DMI is still missing, & efivarfs still fails to load. > > I've been using the kexec_load syscall for all these tests, if it's > important. > > Also, to make it very clear, all this only ever happens post-kexec. When > booting straight from UEFI (with the EFI stub), all the aforementioned > stuff that fails works perfectly fine (i.e. name of firmware is printed, > DMI is properly found, & efivarfs loads & mounts just fine). > > This is reproducible with a vanilla 6.1-rc2 kernel. I've been trying to > bisect it, but it seems like it goes pretty far back. I've got vanilla > mainline kernel builds dating back to 5.17 that have the exact same > issue. It might be worth noting that during this testing, I made sure > the version of the kernel being kexeced & the kernel kexecing were the > same version. It may not have been a problem in older kernels, but that > would be difficult to test for me (a pretty important driver for this > machine was only merged during v5.17-rc4). So it may not have been a > regression & just a hidden problem since time immemorial. > > I am willing to test any patches I may get to further debug or fix > this issue, preferably based on the current state of torvalds/linux.git. > I can build & test kernels quite a few times per day. > > I can also send any important materials (kernel config, dmesg, firmware > information, so on & so forth) on request. I'll also just mention I'm > using kexec-tools 2.0.24 upfront, if it matters. > > Regards, > > _______________________________________________ > kexec mailing list > kexec@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/kexec >
