bisecting fixing commit since fb683b5e3f53a73e761952735736180939a313df building syzkaller on 08003f6440deafc4e193b159c4acece64f7864b1 testing commit fb683b5e3f53a73e761952735736180939a313df with gcc (GCC) 8.1.0 kernel signature: 87e7f380e7c30dedc329a15646304dc0e50b0e16b48ee770eef1cea847a55d59 all runs: crashed: kernel BUG at arch/x86/kvm/mmu.c:LINE! testing current HEAD 5692097116094a4a7045abcc1dbc172dbdc5657e testing commit 5692097116094a4a7045abcc1dbc172dbdc5657e with gcc (GCC) 8.1.0 kernel signature: 5463685cd86e8a65466303ed2f50dda8b4cd02968410e438d85a64755f221a1b all runs: crashed: kernel BUG at arch/x86/kvm/mmu.c:LINE! revisions tested: 2, total time: 25m52.249168704s (build: 18m5.472611803s, test: 6m33.718923489s) the crash still happens on HEAD commit msg: Linux 4.19.109 crash: kernel BUG at arch/x86/kvm/mmu.c:LINE! IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready ------------[ cut here ]------------ kernel BUG at arch/x86/kvm/mmu.c:3279! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 7323 Comm: syz-executor.3 Not tainted 4.19.109-syzkaller #0 IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:transparent_hugepage_adjust+0x337/0x420 arch/x86/kvm/mmu.c:3279 Code: ee 03 0f b6 04 06 84 c0 74 08 3c 03 0f 8e e4 00 00 00 8b 41 30 c1 e8 1f e9 03 ff ff ff 48 89 df e8 ae 04 84 00 e9 fe fc ff ff <0f> 0b 48 89 c7 48 89 55 c8 48 89 4d d0 e8 97 04 84 00 48 8b 55 c8 RSP: 0018:ffff888090aa7528 EFLAGS: 00010202 RAX: 0000000000000003 RBX: ffff888090aa76c0 RCX: 0000000000000009 RDX: 0000000000000004 RSI: dffffc0000000000 RDI: ffff8880775408f8 RBP: ffff888090aa7568 R08: 0000000000000001 R09: 1ffff1100eea811a R10: ffffed100eea9799 R11: ffff88807754bccb R12: 0000000000091d21 R13: 0000000000091d23 R14: ffff88808c920040 R15: ffff888090aa7680 FS: 00007f39bb9b3700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000009fe6a000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tdp_page_fault+0x388/0x540 arch/x86/kvm/mmu.c:4196 kvm_mmu_page_fault+0x163/0x1240 arch/x86/kvm/mmu.c:5342 handle_ept_violation+0x16c/0x380 arch/x86/kvm/vmx.c:7717 vmx_handle_exit+0x1b5/0x11b0 arch/x86/kvm/vmx.c:10199 vcpu_enter_guest+0xd48/0x5120 arch/x86/kvm/x86.c:7850 vcpu_run arch/x86/kvm/x86.c:7913 [inline] kvm_arch_vcpu_ioctl_run+0x2e9/0x1340 arch/x86/kvm/x86.c:8113 kvm_vcpu_ioctl+0x535/0xb60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2667 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: 0033:0x45a909 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f39bb9b2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a909 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f39bb9b36d4 R13: 00000000004c410f R14: 00000000004d9758 R15: 00000000ffffffff Modules linked in: ---[ end trace 6a4af67b287c877d ]--- RIP: 0010:transparent_hugepage_adjust+0x337/0x420 arch/x86/kvm/mmu.c:3279 Code: ee 03 0f b6 04 06 84 c0 74 08 3c 03 0f 8e e4 00 00 00 8b 41 30 c1 e8 1f e9 03 ff ff ff 48 89 df e8 ae 04 84 00 e9 fe fc ff ff <0f> 0b 48 89 c7 48 89 55 c8 48 89 4d d0 e8 97 04 84 00 48 8b 55 c8 RSP: 0018:ffff888090aa7528 EFLAGS: 00010202 RAX: 0000000000000003 RBX: ffff888090aa76c0 RCX: 0000000000000009 RDX: 0000000000000004 RSI: dffffc0000000000 RDI: ffff8880775408f8 RBP: ffff888090aa7568 R08: 0000000000000001 R09: 1ffff1100eea811a R10: ffffed100eea9799 R11: ffff88807754bccb R12: 0000000000091d21 R13: 0000000000091d23 R14: ffff88808c920040 R15: ffff888090aa7680 FS: 00007f39bb9b3700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000009fe6a000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400