Hi,
I've tried to play with kexec using lkvm. Unfortunately, lkvm crashes when
I try to switch to crashkernel.
I use Linus tree + penberg/kvmtool/next + one x86 mm patch[1].
Kernel is defconfig + kvmconfig. I use the same kernel image for system and
crash env.
Host:
% lkvm run --cpus 1 -m 1024 --params 'crashkernel=256M loglevel=8'
Guest:
# kexec -p bzImage --reuse-cmdline
# echo c > /proc/sysrq-trigger
...
[ 0.947984] loop: module loaded
[ 0.950078] virtio-pci 0000:00:01.0: irq 40 for MSI/MSI-X
[ 0.950925] virtio-pci 0000:00:01.0: irq 41 for MSI/MSI-X
[ 0.952944] virtio-pci 0000:00:01.0: irq 42 for MSI/MSI-X
zsh: segmentation fault (core dumped) lkvm run --cpus 1 -m 1024 --params 'crashkernel=256M loglevel=8'
Guest kernel is somewhere in virtio_net initialization (for the second
time). I'm too lazy to find exact line.
Backtrace:
0 irq__add_msix_route (kvm=kvm@entry=0xbf8010, msg=0xe3d090) at x86/irq.c:210
#1 0x000000000041b3bf in virtio_pci__specific_io_out.isra.5 (offset=<optimized out>,
data=<optimized out>, kvm=0xbf8010) at virtio/pci.c:150
#2 virtio_pci__io_out.9406 (ioport=<optimized out>, kvm=0xbf8010, port=<optimized out>,
data=<optimized out>, size=<optimized out>) at virtio/pci.c:208
#3 0x000000000040f8c3 in kvm__emulate_io (count=<optimized out>, size=2, direction=1,
data=<optimized out>, port=25108, kvm=0xbf8010) at ioport.c:165
#4 kvm_cpu__start (cpu=<optimized out>) at x86/include/kvm/kvm-cpu-arch.h:41
#5 0x0000000000416ca2 in kvm_cpu_thread.2824 (arg=<optimized out>) at builtin-run.c:176
#6 0x00007f701ebd0b50 in start_thread (arg=<optimized out>) at pthread_create.c:304
#7 0x00007f701e1fe70d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#8 0x0000000000000000 in ?? ()
[1] https://patchwork.kernel.org/patch/1608411/
--
Kirill A. Shutemov
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