bisecting fixing commit since fb683b5e3f53a73e761952735736180939a313df building syzkaller on 101194ebf6834198300032f6fb438f2c4cdf0401 testing commit fb683b5e3f53a73e761952735736180939a313df with gcc (GCC) 8.1.0 kernel signature: 6009613e348c448fa96ca9120588d309b84b78e16d8c9219d934bef79551d9b2 all runs: crashed: kernel BUG at fs/btrfs/volumes.c:LINE! testing current HEAD 7edd66cf61670d2d0c31f89cb3a247016e489a8a testing commit 7edd66cf61670d2d0c31f89cb3a247016e489a8a with gcc (GCC) 8.1.0 kernel signature: 0b7ec192ff99eafdb9fc08513016fe53af1b06dbde2d2dd97e4d4ca24aa617c8 all runs: crashed: kernel BUG at fs/btrfs/volumes.c:LINE! revisions tested: 2, total time: 25m2.953815207s (build: 17m48.017657163s, test: 6m7.364548516s) the crash still happens on HEAD commit msg: Linux 4.19.118 crash: kernel BUG at fs/btrfs/volumes.c:LINE! RDX: 00007f5c0c3a7ae0 RSI: 00000000200001c0 RDI: 00007f5c0c3a7b00 RBP: 000000000075bf20 R08: 00007f5c0c3a7b40 R09: 00007f5c0c3a7ae0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5c0c3a86d4 R13: 00000000004cac23 R14: 00000000004e4130 R15: 0000000000000003 ------------[ cut here ]------------ kernel BUG at fs/btrfs/volumes.c:1073! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 7456 Comm: syz-executor.2 Not tainted 4.19.118-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:1073 [inline] RIP: 0010:close_fs_devices.part.45+0x4ed/0x7a0 fs/btrfs/volumes.c:1092 Code: 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 79 cc e5 fe e9 a7 fb ff ff e8 6f cc e5 fe e9 a0 RSP: 0018:ffff88808f2076d8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888098745b40 RCX: 0000000000000000 RDX: 1ffffffff10a40d9 RSI: ffffffff88590520 RDI: 0000000000000282 RBP: ffff88808f207748 R08: ffffed1015d44733 R09: ffffed1015d44732 R10: ffffed1015d44732 R11: ffff8880aea23993 R12: dffffc0000000000 R13: ffff888091053b58 R14: ffff888098745b60 R15: ffff88808eccb240 FS: 00007f5c0c3a8700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000075c091 CR3: 000000009115c000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: close_fs_devices fs/btrfs/volumes.c:1124 [inline] btrfs_close_devices+0x80/0x1b0 fs/btrfs/volumes.c:1110 btrfs_mount_root+0xeb4/0x16f0 fs/btrfs/super.c:1619 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+0x21a/0x12f5 fs/btrfs/super.c:1670 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: 0033:0x45d29a Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4d 8c 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 2a 8c fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f5c0c3a7a68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f5c0c3a7c90 RCX: 000000000045d29a RDX: 00007f5c0c3a7ae0 RSI: 00000000200001c0 RDI: 00007f5c0c3a7b00 RBP: 000000000075bf20 R08: 00007f5c0c3a7b40 R09: 00007f5c0c3a7ae0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5c0c3a86d4 R13: 00000000004cac23 R14: 00000000004e4130 R15: 0000000000000003 Modules linked in: ---[ end trace d7362ee362a5f181 ]--- RIP: 0010:btrfs_close_one_device fs/btrfs/volumes.c:1073 [inline] RIP: 0010:close_fs_devices.part.45+0x4ed/0x7a0 fs/btrfs/volumes.c:1092 Code: 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 79 cc e5 fe e9 a7 fb ff ff e8 6f cc e5 fe e9 a0 RSP: 0018:ffff88808f2076d8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888098745b40 RCX: 0000000000000000 RDX: 1ffffffff10a40d9 RSI: ffffffff88590520 RDI: 0000000000000282 RBP: ffff88808f207748 R08: ffffed1015d44733 R09: ffffed1015d44732 R10: ffffed1015d44732 R11: ffff8880aea23993 R12: dffffc0000000000 R13: ffff888091053b58 R14: ffff888098745b60 R15: ffff88808eccb240 FS: 00007f5c0c3a8700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7dee1fe3d8 CR3: 000000009115c000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400