bisecting fixing commit since fb683b5e3f53a73e761952735736180939a313df building syzkaller on 101194ebf6834198300032f6fb438f2c4cdf0401 testing commit fb683b5e3f53a73e761952735736180939a313df with gcc (GCC) 8.4.1 20210217 kernel signature: e1d935f4a4c71d6837201bca404f42e8995569d6ab073615457999ba0b4639e1 all runs: crashed: kernel BUG in close_fs_devices testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: d08120218cf934b979cb733b72257598483dfe3603768cb3d920cc91830c049d all runs: crashed: kernel BUG in close_fs_devices revisions tested: 2, total time: 28m49.104819569s (build: 21m13.753260942s, test: 6m34.098035068s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: kernel BUG in close_fs_devices RDX: 00007f803e1f7020 RSI: 00000000200001c0 RDI: 00007f803e1f7040 RBP: 00007f803e1f7040 R08: 00007f803e1f7080 R09: 00007f803e1f7020 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000004fd190 R14: 00000000004b6840 R15: 00007f803e1f76bc ------------[ cut here ]------------ kernel BUG at fs/btrfs/volumes.c:1062! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 6823 Comm: syz-executor.1 Not tainted 4.19.191-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:1062 [inline] RIP: 0010:close_fs_devices.part.48+0x4ed/0x7a0 fs/btrfs/volumes.c:1081 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 99 e7 e6 fe e9 a7 fb ff ff e8 8f e7 e6 fe e9 a0 RSP: 0018:ffff8881d957f788 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881d9466480 RCX: 0000000000000000 RDX: 1ffffffff10a4021 RSI: ffffffff88590260 RDI: 0000000000000286 RBP: ffff8881d957f7f8 R08: ffffed103ed24733 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: ffff8881f6923993 R12: dffffc0000000000 R13: ffff8881cdc045d8 R14: ffff8881d94664a0 R15: ffff8881d0b06940 FS: 00007f803e1f7700(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000052c071 CR3: 00000001dbc1a002 CR4: 00000000001606e0 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/0x2b0 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+0x219/0xc00 fs/btrfs/super.c:1681 mount_fs+0x7f/0x2b0 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+0xb1/0xd0 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: 0033:0x4636da Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 88 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 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:00007f803e1f6fb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000052bf00 RCX: 00000000004636da RDX: 00007f803e1f7020 RSI: 00000000200001c0 RDI: 00007f803e1f7040 RBP: 00007f803e1f7040 R08: 00007f803e1f7080 R09: 00007f803e1f7020 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000004fd190 R14: 00000000004b6840 R15: 00007f803e1f76bc Modules linked in: ---[ end trace b3086815b0a402f3 ]--- RIP: 0010:btrfs_close_one_device fs/btrfs/volumes.c:1062 [inline] RIP: 0010:close_fs_devices.part.48+0x4ed/0x7a0 fs/btrfs/volumes.c:1081 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 99 e7 e6 fe e9 a7 fb ff ff e8 8f e7 e6 fe e9 a0 RSP: 0018:ffff8881d957f788 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881d9466480 RCX: 0000000000000000 RDX: 1ffffffff10a4021 RSI: ffffffff88590260 RDI: 0000000000000286 RBP: ffff8881d957f7f8 R08: ffffed103ed24733 R09: ffffed103ed24732 R10: ffffed103ed24732 R11: ffff8881f6923993 R12: dffffc0000000000 R13: ffff8881cdc045d8 R14: ffff8881d94664a0 R15: ffff8881d0b06940 FS: 00007f803e1f7700(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000052c071 CR3: 00000001dbc1a005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400