syzbot
BUG: unable to handle kernel paging request in balance_internal
Status:
upstream: reported C repro on 2026/03/30 03:10
Reported-by: syzbot+7a24548bcd165232f4c1@syzkaller.appspotmail.com
First crash: 228d, last: 32d
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Bug presence (1)
| Date |
Name |
Commit |
Repro |
Result |
| 2026/10/06 |
upstream (ToT) |
2c3418fffa9d |
C
|
Failed due to an error; will retry later
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Fix bisection attempts (3)
Sample crash report:
REISERFS warning (device loop0): vs-13060 reiserfs_update_sd_size: stat data of object [2 2 0x0 SD] (nlink == 1) not found (pos 0)
REISERFS warning (device loop0): vs-13060 reiserfs_update_sd_size: stat data of object [2 2 0x0 SD] (nlink == 1) not found (pos 0)
Unable to handle kernel paging request at virtual address dfff800000000003
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000003] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4461 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : balance_internal_when_delete fs/reiserfs/ibalance.c:675 [inline]
pc : balance_internal+0x21e8/0x3e34 fs/reiserfs/ibalance.c:849
lr : balance_internal_when_delete fs/reiserfs/ibalance.c:668 [inline]
lr : balance_internal+0x21b8/0x3e34 fs/reiserfs/ibalance.c:849
sp : ffff800021f46980
x29: ffff800021f46bc0 x28: 0000000000000000 x27: 0000000000000001
x26: ffff800021f46de8 x25: dfff800000000000 x24: 0000000000000000
x23: dfff800000000000 x22: 0000000000000000 x21: 0000000000000018
x20: ffff800021f46de0 x19: 0000000000000001 x18: 1fffe00033c1877e
x17: ffff80001641d000 x16: ffff800011bcac18 x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe0001c074691 x12: 0000000000000000
x11: ff00800008ce355c x10: 0000000000000000 x9 : ffff800008ce355c
x8 : 0000000000000003 x7 : 49ce0fe700000213 x6 : 49ce0fe700000213
x5 : ffff0000e857d020 x4 : ffff0000e857d030 x3 : ffff800008d01d70
x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
balance_internal_when_delete fs/reiserfs/ibalance.c:675 [inline]
balance_internal+0x21e8/0x3e34 fs/reiserfs/ibalance.c:849
do_balance+0x2b0/0x794 fs/reiserfs/do_balan.c:1896
reiserfs_delete_solid_item+0x760/0xc8c fs/reiserfs/stree.c:1462
remove_save_link+0x1e4/0x350 fs/reiserfs/super.c:540
reiserfs_truncate_file+0x540/0xb04 fs/reiserfs/inode.c:2322
reiserfs_setattr+0xad4/0x1014 fs/reiserfs/inode.c:3395
notify_change+0xb5c/0xe20 fs/attr.c:499
do_truncate+0x188/0x20c fs/open.c:65
handle_truncate fs/namei.c:3336 [inline]
do_open fs/namei.c:3681 [inline]
path_openat+0x21c8/0x27a0 fs/namei.c:3834
do_filp_open+0x198/0x38c fs/namei.c:3861
do_sys_openat2+0x134/0x3fc fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__arm64_sys_openat+0x11c/0x150 fs/open.c:1347
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d2d00017 f2fbfff7 910062d5 d343fea8 (38776908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: d2d00017 mov x23, #0x800000000000 // #140737488355328
4: f2fbfff7 movk x23, #0xdfff, lsl #48
8: 910062d5 add x21, x22, #0x18
c: d343fea8 lsr x8, x21, #3
* 10: 38776908 ldrb w8, [x8, x23] <-- trapping instruction
Struck through repros no longer work on HEAD.