syzbot
kernel BUG in btrfs_free_tree_block (2)
Status:
upstream: reported syz repro on 2026/07/29 07:23
Bug presence:
origin:lts-only
[Documentation on labels]
Reported-by: syzbot+1e47e820a43a89a9e5e4@syzkaller.appspotmail.com
First crash: 103d, last: 5h52m
▶
▼
Last patch testing requests (1)
Sample crash report:
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37c1c97038 R14: 00007f37c1c96fa0 R15: 00007ffcfa1bdc68
</TASK>
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent-tree.c:3311!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4566 Comm: syz.0.23 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:btrfs_free_tree_block+0xb71/0xb80 fs/btrfs/extent-tree.c:3311
Code: e9 02 f9 ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 07 f9 ff ff be 08 00 00 00 4c 89 e7 e8 69 fb 78 fe e9 f5 f8 ff ff e8 6f b2 33 fe <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 41 57 41 56 41 55
RSP: 0018:ffffc9000384f5a0 EFLAGS: 00010293
RAX: ffffffff83457b21 RBX: 1ffff11005a58c62 RCX: ffff88802d345940
RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000
RBP: ffffc9000384f6f0 R08: ffffffff9104720f R09: 1ffffffff2208e41
R10: dffffc0000000000 R11: fffffbfff2208e42 R12: ffff88806150b064
R13: ffff88802d2c6310 R14: 00000000fffffff4 R15: 0000000000000005
FS: 00007f37c106f6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f37c1a5e200 CR3: 000000005fae7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
btrfs_force_cow_block+0xc4d/0x1760 fs/btrfs/ctree.c:480
btrfs_cow_block+0x33e/0x7d0 fs/btrfs/ctree.c:598
btrfs_search_slot+0x9d4/0x2090 fs/btrfs/ctree.c:-1
btrfs_insert_empty_items+0x32c/0x3e0 fs/btrfs/ctree.c:4012
btrfs_new_inode+0x908/0x1830 fs/btrfs/inode.c:6674
btrfs_mkdir+0x2ac/0x5b0 fs/btrfs/inode.c:7072
vfs_mkdir+0x386/0x570 fs/namei.c:4116
do_mkdirat+0x1dd/0x5c0 fs/namei.c:4141
__do_sys_mkdirat fs/namei.c:4156 [inline]
__se_sys_mkdirat fs/namei.c:4154 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4154
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f37c1a10b19
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f37c106f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f37c1c96fa0 RCX: 00007f37c1a10b19
RDX: 00000000000001ff RSI: 0000200000007040 RDI: ffffffffffffff9c
RBP: 00007f37c1aa8b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f37c1c97038 R14: 00007f37c1c96fa0 R15: 00007ffcfa1bdc68
</TASK>
Modules linked in:
---[ end trace a5d16897b868bc91 ]---
RIP: 0010:btrfs_free_tree_block+0xb71/0xb80 fs/btrfs/extent-tree.c:3311
Code: e9 02 f9 ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 07 f9 ff ff be 08 00 00 00 4c 89 e7 e8 69 fb 78 fe e9 f5 f8 ff ff e8 6f b2 33 fe <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 41 57 41 56 41 55
RSP: 0018:ffffc9000384f5a0 EFLAGS: 00010293
RAX: ffffffff83457b21 RBX: 1ffff11005a58c62 RCX: ffff88802d345940
RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000
RBP: ffffc9000384f6f0 R08: ffffffff9104720f R09: 1ffffffff2208e41
R10: dffffc0000000000 R11: fffffbfff2208e42 R12: ffff88806150b064
R13: ffff88802d2c6310 R14: 00000000fffffff4 R15: 0000000000000005
FS: 00007f37c106f6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005561572a6160 CR3: 000000005fae7000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
* Struck through repros no longer work on HEAD.