Q: tests/ioctl_kvm_run.c segfaults on rawhide

[Dmitry V. Levin]

On Tue, Jul 03, 2018 at 11:32:06PM +0300, Dmitry V. Levin wrote:
> Hi,
> 
> Our ioctl_kvm_run test started to fail on rawhide with the following symptoms:
> 
> strace/tests$ $ ./ioctl_kvm_run >/dev/null; echo \$?=$?
> $?=0
> strace/tests-m32$ ./ioctl_kvm_run >/dev/null; echo \$?=$?
> Segmentation fault (core dumped)
> $?=139
> strace/tests-m32$ ../strace -enone ./ioctl_kvm_run >/dev/null 
> ../strace: [ Process PID=12345 runs in 32 bit mode. ]
> +++ exited with 0 +++
> 
> The segfault happens inside glibc right after the first ioctl(KVM_RUN)
> invocation.
> 
> All this oddness is happening in the following system:
> Linux rawhide-test.fedorainfracloud.org 4.18.0-0.rc2.git4.1.fc29.x86_64 #1 SMP Fri Jun 29 15:03:54 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

The same symptoms could be seen in the following system:
Linux f27-test.fedorainfracloud.org 4.17.3-100.fc27.x86_64 #1 SMP Tue Jun 26 14:19:03 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

This essentially leaves the kernel as the only plausible cause of this bug.

> There are no such problems in the following system:
> Linux f28-test.fedorainfracloud.org 4.16.3-301.fc28.x86_64 #1 SMP Mon Apr 23 21:59:58 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
> 
> I suspect it's a bug of kvm nesting in rawhide, most likely in the kernel.
> Any ideas where to report this?


-- 
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