bisecting fixing commit since a89b48fe9308d976d9dcb2112e264d647f7efce4 building syzkaller on 6c236867ce33c0c16b102e02a08226d7eb9b2046 testing commit a89b48fe9308d976d9dcb2112e264d647f7efce4 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 084f76f7c4b078982461041dace6c6359501e7d27da1f799642a6f245e52752b run #0: crashed: kernel BUG in kvm_hv_set_msr_common run #1: crashed: kernel BUG in kvm_hv_set_msr_common run #2: crashed: kernel BUG in kvm_hv_set_msr_common run #3: crashed: kernel BUG in kvm_hv_set_msr_common run #4: crashed: kernel BUG in kvm_hv_set_msr_common run #5: crashed: kernel BUG in kvm_hv_set_msr_common run #6: crashed: kernel BUG in kvm_hv_set_msr_common run #7: crashed: kernel BUG in kvm_hv_set_msr_common run #8: crashed: kernel BUG in kvm_hv_set_msr_common run #9: crashed: kernel BUG in kvm_hv_set_msr_common run #10: crashed: kernel BUG in kvm_hv_set_msr_common run #11: OK run #12: OK run #13: crashed: kernel BUG in kvm_hv_set_msr_common run #14: OK run #15: OK run #16: OK run #17: OK run #18: OK run #19: OK testing current HEAD e23d55af0e1fca9be5c99f0c37d48b289f4d6489 testing commit e23d55af0e1fca9be5c99f0c37d48b289f4d6489 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 18e8ede46059d39e5d5b8949208fa111d244d93d3bf08232b41cb551603e39db run #0: crashed: kernel BUG in kvm_hv_set_msr_common run #1: crashed: kernel BUG in kvm_hv_set_msr_common run #2: crashed: kernel BUG in kvm_hv_set_msr_common run #3: crashed: kernel BUG in kvm_hv_set_msr_common run #4: crashed: kernel BUG in kvm_hv_set_msr_common run #5: crashed: kernel BUG in kvm_hv_set_msr_common run #6: OK run #7: OK run #8: OK run #9: OK revisions tested: 2, total time: 36m6.376161588s (build: 17m55.812483809s, test: 17m40.044038282s) the crash still happens on HEAD commit msg: Linux 4.19.205 crash: kernel BUG in kvm_hv_set_msr_common ------------[ cut here ]------------ kernel BUG at include/linux/kvm_host.h:560! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 24847 Comm: syz-executor.0 Not tainted 4.19.205-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline] RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline] RIP: 0010:kvm_hv_set_msr_common+0x1e08/0x24b0 arch/x86/kvm/hyperv.c:1285 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1d 01 00 00 48 8b 85 f0 fe ff ff 45 31 ed 48 89 83 a0 4c 00 00 e9 09 e4 ff ff <0f> 0b e8 11 7a 76 00 e9 89 e8 ff ff 48 89 df e8 04 7a 76 00 e9 bc RSP: 0018:ffff888092ad7240 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8880abf20e80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc900074959d0 RBP: ffff888092ad7380 R08: fffff52000e92b3b R09: fffff52000e92b3a R10: fffff52000e92b3a R11: ffffc900074959d3 R12: 0000000000000000 R13: ffffc900074959d0 R14: dffffc0000000000 R15: ffffc90007495000 FS: 00007f1e759b3700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055bbee48fff8 CR3: 0000000096dbf000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kvm_set_msr_common+0x6e7/0x1fb0 arch/x86/kvm/x86.c:2629 vmx_set_msr+0x3bf/0x1ba0 arch/x86/kvm/vmx.c:4317 kvm_set_msr+0x130/0x330 arch/x86/kvm/x86.c:1346 do_set_msr+0x85/0xe0 arch/x86/kvm/x86.c:1375 __msr_io arch/x86/kvm/x86.c:2943 [inline] msr_io+0x125/0x200 arch/x86/kvm/x86.c:2979 kvm_arch_vcpu_ioctl+0x166d/0x2520 arch/x86/kvm/x86.c:3974 kvm_vcpu_ioctl+0x1eb/0xb60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2998 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1e759b3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665e9 RDX: 0000000020001a40 RSI: 000000004008ae89 RDI: 0000000000000005 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038 R13: 00007fff4415bd9f R14: 00007f1e759b3300 R15: 0000000000022000 Modules linked in: ---[ end trace ba462fb668f95f0e ]--- RIP: 0010:kvm_vcpu_get_idx include/linux/kvm_host.h:560 [inline] RIP: 0010:kvm_hv_set_msr arch/x86/kvm/hyperv.c:1070 [inline] RIP: 0010:kvm_hv_set_msr_common+0x1e08/0x24b0 arch/x86/kvm/hyperv.c:1285 Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1d 01 00 00 48 8b 85 f0 fe ff ff 45 31 ed 48 89 83 a0 4c 00 00 e9 09 e4 ff ff <0f> 0b e8 11 7a 76 00 e9 89 e8 ff ff 48 89 df e8 04 7a 76 00 e9 bc RSP: 0018:ffff888092ad7240 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8880abf20e80 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc900074959d0 RBP: ffff888092ad7380 R08: fffff52000e92b3b R09: fffff52000e92b3a R10: fffff52000e92b3a R11: ffffc900074959d3 R12: 0000000000000000 R13: ffffc900074959d0 R14: dffffc0000000000 R15: ffffc90007495000 FS: 00007f1e759b3700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000540198 CR3: 0000000096dbf000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400