Re: boot failure of linux-next due to 1248fb6a8201 ("x86/mm: Randomize per-cpu entry area")

[Kees Cook <keescook@chromium.org>]

On Fri, Oct 28, 2022 at 02:29:14PM +0100, Sudip Mukherjee (Codethink) wrote:
> Hi All,
> 
> Our qemu boots were failing since next-20221024, and a git bisect of
> next-20221028 showed the bad commit as 1248fb6a8201 ("x86/mm: Randomize per-cpu entry area")
> 
> After reverting the commit I could boot qemu again with next-20221028.
> 
> This is my config:
> 
> make defconfig
> make kvm_guest.config
> scripts/config -e KCOV -e KCOV_INSTRUMENT_ALL -e KCOV_ENABLE_COMPARISONS -e DEBUG_FS -e DEBUG_KMEMLEAK -e DEBUG_INFO -e KALLSYMS -e KALLSYMS_ALL -e NAMESPACES -e UTS_NS -e IPC_NS -e PID_NS -e NET_NS -e CGROUP_PIDS -e MEMCG -e USER_NS -e CONFIGFS_FS -e SECURITYFS -e KASAN -e KASAN_INLINE -e FAULT_INJECTION -e FAULT_INJECTION_DEBUG_FS -e FAULT_INJECTION_USERCOPY -e FAILSLAB -e FAIL_PAGE_ALLOC -e FAIL_MAKE_REQUEST -e FAIL_IO_TIMEOUT -e FAIL_FUTEX -e LOCKDEP -e PROVE_LOCKING -e DEBUG_ATOMIC_SLEEP -e PROVE_RCU -e DEBUG_VM -e REFCOUNT_FULL -e FORTIFY_SOURCE -e HARDENED_USERCOPY -e LOCKUP_DETECTOR -e SOFTLOCKUP_DETECTOR -e HARDLOCKUP_DETECTOR -e BOOTPARAM_HARDLOCKUP_PANIC -e DETECT_HUNG_TASK -e WQ_WATCHDOG -e USB_GADGET -e USB_RAW_GADGET -e TUN -e KCSAN -d RANDOMIZE_BASE -e MAC80211_HWSIM -e IEEE802154 -e MAC802154 -e IEEE802154_DRIVERS -e IEEE802154_HWSIM -e BT -e BT_HCIVHCI
> echo "CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=140" >> .config
> echo "CONFIG_RCU_CPU_STALL_TIMEOUT=100" >> .config
> 
> I will be happy to test any patch or provide any extra log if needed.
> Though I am not sure how I will collect extra logs (if needed) as there
> was no output from qemu.

I see KASAN in your config, does this fix it?

https://lore.kernel.org/lkml/166693938482.29415.7034851115705424459.tip-bot2@tip-bot2/


-- 
Kees Cook