kernel BUG in balance_leaf (2)

Status: upstream: reported C repro on 2025/06/02 02:17
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+1a932d66673a8b904c5d@syzkaller.appspotmail.com
First crash: 429d, last: 42d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/06/03 linux-5.15.y (ToT) 98f47d0e9b8c C [report] kernel BUG in balance_leaf
2025/06/03 upstream (ToT) 546b1c9e93c2 C Didn't crash
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 kernel BUG in balance_leaf (2) origin:lts-only -1 syz, C inconclusive 5 207d 229d 0/3 upstream: reported C repro on 2025/12/19 10:25
linux-6.6 kernel BUG in balance_leaf origin:lts-only -1 syz, C inconclusive 3 221d 221d 0/2 upstream: reported C repro on 2025/12/26 19:48
linux-4.14 kernel BUG in balance_leaf reiserfs -1 syz, C 1 1275d 1305d 0/1 upstream: reported C repro on 2023/01/08 11:53
upstream kernel BUG in balance_leaf fs -1 syz, C error done 16 957d 1309d 25/29 fixed on 2024/01/30 15:47
linux-4.19 kernel BUG in balance_leaf reiserfs -1 syz, C error 1 1299d 1299d 0/1 upstream: reported C repro on 2023/01/13 23:48
linux-5.15 kernel BUG in balance_leaf -1 1 668d 668d 0/3 auto-obsoleted due to no activity on 2025/01/14 15:53
linux-6.1 kernel BUG in balance_leaf -1 4 1200d 1210d 0/3 auto-obsoleted due to no activity on 2023/08/21 17:28
▶ ▼ Last patch testing requests (5)
Created Duration User Patch Repo Result
2026/06/24 07:55 17m retest repro linux-5.15.y report log
2026/04/15 04:02 10m retest repro linux-5.15.y report log
2026/02/04 01:57 10m retest repro linux-5.15.y report log
2025/11/25 17:57 10m retest repro linux-5.15.y report log
2025/09/16 16:19 10m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (6)
Created Duration User Patch Repo Result
2026/05/08 15:33 18m fix candidate upstream error job log
2026/03/25 18:21 1m fix candidate upstream error job log
2026/02/22 23:36 1m fix candidate upstream error job log
2026/01/23 12:49 1m fix candidate upstream error job log
2025/12/22 08:21 6m fix candidate upstream error job log
2025/07/05 17:11 0m bisect fix linux-5.15.y error job log

Sample crash report:
REISERFS panic (device loop0): vs-12195 balance_leaf: CFR not initialized
------------[ cut here ]------------
kernel BUG at fs/reiserfs/prints.c:390!
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4027 Comm: syz-executor588 Not tainted 5.15.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
lr : __reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
sp : ffff80001f0f62e0
x29: ffff80001f0f6380 x28: ffff80001f0f6b80 x27: ffff80001f0f6b98
x26: 3000000000000000 x25: dfff800000000000 x24: ffff80001f0f6d20
x23: ffff80001f0f6300 x22: ffff8000113e1ea0 x21: ffff0000d66bc000
x20: ffff8000113e1e80 x19: ffff800013870e79 x18: 0000000000000002
x17: 0000000040000000 x16: ffff8000111a5644 x15: 0000000000000002
x14: 0000000000ff0100 x13: 1ffff0000282a06b x12: 0000000000ff0100
x11: 0000000000000000 x10: 0000000000000000 x9 : 4487240a33273000
x8 : 4487240a33273000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000000 x3 : ffff80000a732644
x2 : ffff0001a111cd10 x1 : 0000000100000000 x0 : 0000000000000049
Call trace:
 __reiserfs_panic+0x13c/0x140 fs/reiserfs/prints.c:384
 balance_leaf+0xa0a8/0xd2f4 fs/reiserfs/do_balan.c:1439
 do_balance+0x260/0x778 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x5b4/0x6d0 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x1458/0x34b0 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x3e4/0x1588 fs/buffer.c:2012
 __block_write_begin+0x40/0x54 fs/buffer.c:2062
 reiserfs_write_begin+0x3c8/0x654 fs/reiserfs/inode.c:2790
 generic_perform_write+0x204/0x480 mm/filemap.c:3785
 __generic_file_write_iter+0x23c/0x454 mm/filemap.c:3912
 generic_file_write_iter+0xb0/0x1b4 mm/filemap.c:3944
 do_iter_readv_writev+0x3a0/0x4f8 fs/read_write.c:-1
 do_iter_write+0x1c4/0x670 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_pwritev+0x1c8/0x2fc fs/read_write.c:1025
 __do_sys_pwritev2 fs/read_write.c:1084 [inline]
 __se_sys_pwritev2 fs/read_write.c:1075 [inline]
 __arm64_sys_pwritev2+0xd4/0x108 fs/read_write.c:1075
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 912800a5 911aa2a1 aa1303e4 97ffd888 (d4210000) 
---[ end trace 8c0dd424965e71fd ]---

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/02 08:42 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-5-15-kasan-arm64 kernel BUG in balance_leaf
2025/07/12 22:40 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 kernel BUG in balance_leaf
2025/06/02 02:16 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 kernel BUG in balance_leaf
* Struck through repros no longer work on HEAD.