bisecting fixing commit since fb683b5e3f53a73e761952735736180939a313df building syzkaller on 101194ebf6834198300032f6fb438f2c4cdf0401 testing commit fb683b5e3f53a73e761952735736180939a313df with gcc (GCC) 8.1.0 kernel signature: e05512aef1b64610969515dd336f1dce403c5091a842a66c8df47532889eb10d all runs: crashed: kernel BUG at fs/btrfs/volumes.c:LINE! testing current HEAD daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b testing commit daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b with gcc (GCC) 8.1.0 kernel signature: aafe9ece22d3d91ef38fa89712b7b95f9792083cae873639a9cb1134f6d437d0 all runs: crashed: kernel BUG at fs/btrfs/volumes.c:LINE! revisions tested: 2, total time: 28m31.749106864s (build: 21m10.336577179s, test: 6m18.425773298s) the crash still happens on HEAD commit msg: Linux 4.19.161 crash: kernel BUG at fs/btrfs/volumes.c:LINE! RDX: 00007f5cedc9dae0 RSI: 00000000200001c0 RDI: 00007f5cedc9db00 RBP: 000000000075bf20 R08: 00007f5cedc9db40 R09: 00007f5cedc9dae0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5cedc9e6d4 R13: 00000000004caca3 R14: 00000000004e41b0 R15: 0000000000000003 ------------[ cut here ]------------ kernel BUG at fs/btrfs/volumes.c:1057! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 6835 Comm: syz-executor.2 Not tainted 4.19.161-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:btrfs_close_one_device fs/btrfs/volumes.c:1057 [inline] RIP: 0010:close_fs_devices.part.48+0x4eb/0x7a0 fs/btrfs/volumes.c:1081 Code: 0f 85 9e 01 00 00 48 8d 7a 30 4c 89 43 18 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 85 6a 01 00 00 48 83 6a 30 01 e9 45 fc ff ff <0f> 0b 0f 0b 4c 89 f7 e8 09 fe e3 fe e9 a7 fb ff ff e8 ff fd e3 fe RSP: 0018:ffff8881de74f788 EFLAGS: 00010202 RAX: fffffffffffffff4 RBX: ffff8881dd742900 RCX: 1ffff1103bb49d32 RDX: 0000000000000000 RSI: ffff8881dda4e970 RDI: 0000000000000282 RBP: ffff8881de74f7f8 R08: ffff8881dda4e990 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8881e31ef918 R14: ffff8881dd742920 R15: fffffffffffffff4 FS: 00007f5cedc9e700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f02ac036058 CR3: 00000001dee46006 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: close_fs_devices fs/btrfs/volumes.c:1113 [inline] btrfs_close_devices+0x80/0x1b0 fs/btrfs/volumes.c:1099 btrfs_mount_root+0xeb4/0x16f0 fs/btrfs/super.c:1630 mount_fs+0x7f/0x2a2 fs/super.c:1261 vfs_kern_mount.part.34+0x58/0x3d0 fs/namespace.c:961 vfs_kern_mount+0xe/0x20 fs/namespace.c:947 btrfs_mount+0x219/0xbd3 fs/btrfs/super.c:1681 mount_fs+0x7f/0x2a2 fs/super.c:1261 vfs_kern_mount.part.34+0x58/0x3d0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2469 [inline] do_mount+0x36e/0x2410 fs/namespace.c:2799 ksys_mount+0xba/0xe0 fs/namespace.c:3015 __do_sys_mount fs/namespace.c:3029 [inline] __se_sys_mount fs/namespace.c:3026 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d31a Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 cd 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 aa 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f5cedc9da68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f5cedc9dc90 RCX: 000000000045d31a RDX: 00007f5cedc9dae0 RSI: 00000000200001c0 RDI: 00007f5cedc9db00 RBP: 000000000075bf20 R08: 00007f5cedc9db40 R09: 00007f5cedc9dae0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5cedc9e6d4 R13: 00000000004caca3 R14: 00000000004e41b0 R15: 0000000000000003 Modules linked in: ---[ end trace c446b7360425c608 ]--- RIP: 0010:btrfs_close_one_device fs/btrfs/volumes.c:1057 [inline] RIP: 0010:close_fs_devices.part.48+0x4eb/0x7a0 fs/btrfs/volumes.c:1081 Code: 0f 85 9e 01 00 00 48 8d 7a 30 4c 89 43 18 48 89 f8 48 c1 e8 03 42 80 3c 20 00 0f 85 6a 01 00 00 48 83 6a 30 01 e9 45 fc ff ff <0f> 0b 0f 0b 4c 89 f7 e8 09 fe e3 fe e9 a7 fb ff ff e8 ff fd e3 fe RSP: 0018:ffff8881de74f788 EFLAGS: 00010202 RAX: fffffffffffffff4 RBX: ffff8881dd742900 RCX: 1ffff1103bb49d32 RDX: 0000000000000000 RSI: ffff8881dda4e970 RDI: 0000000000000282 RBP: ffff8881de74f7f8 R08: ffff8881dda4e990 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8881e31ef918 R14: ffff8881dd742920 R15: fffffffffffffff4 FS: 00007f5cedc9e700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f02ac036058 CR3: 00000001dee46001 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400