syzbot


kernel BUG in direntry_check_right

Status: upstream: reported on 2026/01/10 05:16
Reported-by: syzbot+243f2adea073f599cad2@syzkaller.appspotmail.com
First crash: 6d01h, last: 6d01h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 kernel BUG in direntry_check_right reiserfs -1 syz error 1 1116d 1116d 0/1 upstream: reported syz repro on 2022/12/26 20:36
linux-6.1 kernel BUG in direntry_check_right missing-backport origin:lts-only -1 C inconclusive 42 15d 295d 0/3 upstream: reported C repro on 2025/03/26 15:43
upstream kernel BUG in direntry_check_right fs -1 C done done 2 755d 798d 25/29 fixed on 2024/01/30 15:47
linux-5.15 kernel BUG in direntry_check_right origin:lts-only -1 C 111 6d10h 152d 0/3 upstream: reported C repro on 2025/08/16 17:50

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/reiserfs/item_ops.c:569!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 6557 Comm: syz.4.115 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:direntry_check_right+0x266/0x270 fs/reiserfs/item_ops.c:569
Code: e9 4b ff ff ff 44 89 f9 80 e1 07 38 c1 0f 8c 51 ff ff ff be 04 00 00 00 4c 89 ff e8 f4 f4 b4 ff e9 3f ff ff ff e8 1a 86 5d ff <0f> 0b e8 13 86 5d ff 0f 0b 90 f3 0f 1e fa 55 41 57 41 56 41 55 41
RSP: 0018:ffffc90003506cd8 EFLAGS: 00010293
RAX: ffffffff82280aa6 RBX: dffffc0000000000 RCX: ffff888018b89e00
RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000000044
RBP: ffff888079a680fe R08: ffff888018b89e00 R09: 0000000000000002
R10: 0000000000000070 R11: 0000000000000000 R12: ffff888079a680fe
R13: 0000000000000020 R14: 0000000000000000 R15: 0000000000000024
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007face2744e9c CR3: 0000000068365000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 check_right+0x4ea/0x7f0 fs/reiserfs/fix_node.c:355
 dc_check_balance_leaf fs/reiserfs/fix_node.c:1983 [inline]
 dc_check_balance fs/reiserfs/fix_node.c:2039 [inline]
 check_balance fs/reiserfs/fix_node.c:2086 [inline]
 fix_nodes+0x3dbb/0x82e0 fs/reiserfs/fix_node.c:2636
 reiserfs_cut_from_item+0x309/0x1f10 fs/reiserfs/stree.c:1740
 reiserfs_do_truncate+0xa3d/0x1340 fs/reiserfs/stree.c:1971
 reiserfs_truncate_file+0x37a/0x7c0 fs/reiserfs/inode.c:2306
 reiserfs_file_release+0x8e4/0xa50 fs/reiserfs/file.c:109
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x90b/0x23c0 kernel/exit.c:883
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x1400 kernel/signal.c:2902
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 irqentry_exit_to_user_mode+0x9/0x40 kernel/entry/common.c:315
 exc_page_fault+0x8f/0x110 arch/x86/mm/fault.c:1524
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608
RIP: 0033:0x7f478c58f751
Code: Unable to access opcode bytes at 0x7f478c58f727.
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f478c7e6090 RCX: 00007f478c58f749
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007f478c613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f478c7e6128 R14: 00007f478c7e6090 R15: 00007ffdac88c0e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:direntry_check_right+0x266/0x270 fs/reiserfs/item_ops.c:569
Code: e9 4b ff ff ff 44 89 f9 80 e1 07 38 c1 0f 8c 51 ff ff ff be 04 00 00 00 4c 89 ff e8 f4 f4 b4 ff e9 3f ff ff ff e8 1a 86 5d ff <0f> 0b e8 13 86 5d ff 0f 0b 90 f3 0f 1e fa 55 41 57 41 56 41 55 41
RSP: 0018:ffffc90003506cd8 EFLAGS: 00010293
RAX: ffffffff82280aa6 RBX: dffffc0000000000 RCX: ffff888018b89e00
RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000000044
RBP: ffff888079a680fe R08: ffff888018b89e00 R09: 0000000000000002
R10: 0000000000000070 R11: 0000000000000000 R12: ffff888079a680fe
R13: 0000000000000020 R14: 0000000000000000 R15: 0000000000000024
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007face2744e9c CR3: 0000000068365000 CR4: 00000000003506f0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/10 05:15 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan kernel BUG in direntry_check_right
* Struck through repros no longer work on HEAD.