[Bug 206669] New: Little-endian kernel crashing on POWER8 on heavy big-endian PowerKVM load

[Nicholas Piggin]

bugzilla-daemon at bugzilla.kernel.org's on February 26, 2020 1:26 am:
> https://bugzilla.kernel.org/show_bug.cgi?id=206669
> 
>             Bug ID: 206669
>            Summary: Little-endian kernel crashing on POWER8 on heavy
>                     big-endian PowerKVM load
>            Product: Platform Specific/Hardware
>            Version: 2.5
>     Kernel Version: 5.4.x
>           Hardware: All
>                 OS: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: PPC-64
>           Assignee: platform_ppc-64 at kernel-bugs.osdl.org
>           Reporter: glaubitz at physik.fu-berlin.de
>                 CC: matorola at gmail.com
>         Regression: No
> 
> Created attachment 287605
>   --> https://bugzilla.kernel.org/attachment.cgi?id=287605&action=edit
> Backtrace of host system crashing with little-endian kernel
> 
> We have an IBM POWER server (8247-42L) running Linux kernel 5.4.13 on Debian
> unstable hosting a big-endian ppc64 virtual machine running the same kernel in
> big-endian mode.
> 
> When building OpenJDK-11 on the big-endian VM, the testsuite crashes the *host*
> system which is little-endian with the following kernel backtrace. The problem
> reproduces both with kernel 4.19.98 as well as 5.4.13, both guest and host
> running 5.4.x.
> 
> Backtrace attached.

Thanks for the report, we need to get more data about the first BUG if 
we can. What function in your vmlinux contains address 
0xc00000000017a778? (use nm or objdump etc) Is that the first message you get,
No warnings or anything else earlier in the dmesg?

Also 0xc0000000002659a0 would be interesting.

When reproducing, do you ever get a clean trace of the first bug? Could
you try setting /proc/sys/kernel/panic_on_oops and reproducing?

Thanks,
Nick