Hello, syzbot found the following crash on: HEAD commit: 7ae77150 Merge tag 'powerpc-5.8-1' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=135e7235100000 kernel config: https://syzkaller.appspot.com/x/.config?x=d195fe572fb15312 dashboard link: https://syzkaller.appspot.com/bug?extid=a99874f5323ce6088e53 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14d001be100000 Bisection is inconclusive: the bug happens on the oldest tested release. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13a8e549100000 final crash: https://syzkaller.appspot.com/x/report.txt?x=1068e549100000 console output: https://syzkaller.appspot.com/x/log.txt?x=17a8e549100000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a99874f5323ce6088e53@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: null-ptr-deref in test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] BUG: KASAN: null-ptr-deref in kvm_arch_check_processor_compat+0x1f8/0x750 arch/x86/kvm/x86.c:9818 Read of size 8 at addr 0000000000000060 by task syz-executor.2/8085 CPU: 1 PID: 8085 Comm: syz-executor.2 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 __kasan_report mm/kasan/report.c:517 [inline] kasan_report.cold+0x5/0x37 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:192 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] kvm_arch_check_processor_compat+0x1f8/0x750 arch/x86/kvm/x86.c:9818 </IRQ> ================================================================== Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 8085 Comm: syz-executor.2 Tainted: G B 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 end_report+0x4d/0x53 mm/kasan/report.c:104 __kasan_report mm/kasan/report.c:520 [inline] kasan_report.cold+0xd/0x37 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x141/0x190 mm/kasan/generic.c:192 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] kvm_arch_check_processor_compat+0x1f8/0x750 arch/x86/kvm/x86.c:9818 </IRQ> Shutting down cpus with NMI Kernel Offset: disabled Rebooting in 86400 seconds.. --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches
