Messages in this thread | | | Date | Tue, 30 Jan 2018 21:42:24 -0800 | From | Eric Biggers <> | Subject | Re: WARNING in __switch_to (2) |
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On Thu, Jan 04, 2018 at 08:58:00PM -0800, syzbot wrote: > Hello, > > syzkaller hit the following crash on > 37759fa6d0fa9e4d6036d19ac12f555bfc0aeafd > git://git.cmpxchg.org/linux-mmots.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+1d7d9ce4ce4a23cb7d3b@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > WARNING: CPU: 0 PID: 3192 at ./arch/x86/include/asm/fpu/internal.h:340 > paravirt_write_msr arch/x86/include/asm/paravirt.h:21 [inline] > WARNING: CPU: 0 PID: 3192 at ./arch/x86/include/asm/fpu/internal.h:340 > wrmsrl arch/x86/include/asm/paravirt.h:149 [inline] > WARNING: CPU: 0 PID: 3192 at ./arch/x86/include/asm/fpu/internal.h:340 > load_seg_legacy arch/x86/kernel/process_64.c:255 [inline] > WARNING: CPU: 0 PID: 3192 at ./arch/x86/include/asm/fpu/internal.h:340 > __switch_to+0x10bd/0x13c0 arch/x86/kernel/process_64.c:455 > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 3192 Comm: syzkaller835319 Not tainted 4.15.0-rc4-mm1+ #49 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > Shutting down cpus with NMI > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user [me m or41y > .3ac65ce0s98s > ] > Rebooting in 86400 seconds.. > ---[ end trace 2d2aa5997809e25d ]---
For some reason I'm not able to reproduce this crash with the reproducer and commit given -- even after making sure I had set kvm_intel.nested=1 on the host since the reproducer uses KVM. And syzbot only hit this from Jan 1 through Jan 3. So I'll assume it was introduced and fixed by the x86 changes around that time, and I'll invalidate the bug for syzbot; it will send a new report if this crash happens again...
#syz invalid
- Eric
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