syzbot
BUG: unable to handle kernel paging request in __hfsplus_brec_find
Status:
moderation: reported on 2026/09/13 20:22
Subsystems:
hfs
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+f957cf00261d1c41fafd@syzkaller.appspotmail.com
First crash: 4d01h, last: 4d01h
Sample crash report:
BUG: unable to handle page fault for address: fffffffffffffffb
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD eb4b067 P4D eb4b067 PUD eb4d067 PMD 0
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5318 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:hfs_bnode_num_recs_invalid fs/hfsplus/hfsplus_fs.h:605 [inline]
RIP: 0010:__hfsplus_brec_find+0xe0/0x850 fs/hfsplus/bfind.c:114
Code: e8 c5 6f 7f ff 4d 85 ff 74 67 48 89 5c 24 38 4c 89 f8 48 c1 e8 03 48 89 44 24 10 42 80 3c 20 00 74 08 4c 89 ff e8 d0 6c 7f ff <49> 8b 1f 48 85 db 74 4b 4c 89 6c 24 28 48 83 c3 38 48 89 d8 48 c1
RSP: 0018:ffffc9000e93f480 EFLAGS: 00010246
RAX: 1fffffffffffffff RBX: ffffc9000e93f820 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000000000ff RDI: ffffc9000e93f834
RBP: ffffc9000e93f570 R08: ffffc9000e93f833 R09: 0000000000000000
R10: ffffc9000e93f820 R11: fffff52001d27f07 R12: dffffc0000000000
R13: ffffc9000e93f800 R14: 1ffff92001d27e98 R15: fffffffffffffffb
FS: 00007f61883236c0(0000) GS:ffff88808c2ca000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffb CR3: 000000001296f000 CR4: 0000000000352ef0
Call Trace:
<TASK>
hfsplus_brec_insert+0x90e/0xde0 fs/hfsplus/brec.c:170
hfsplus_rename_cat+0x5b2/0x1070 fs/hfsplus/catalog.c:481
hfsplus_rename+0x145/0x280 fs/hfsplus/dir.c:596
vfs_rename+0xbd9/0xef0 fs/namei.c:6208
filename_renameat2+0x533/0x9a0 fs/namei.c:6326
__do_sys_rename fs/namei.c:6370 [inline]
__se_sys_rename+0x55/0x2c0 fs/namei.c:6366
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f618739e159
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:00007f6188322fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f6187626090 RCX: 00007f618739e159
RDX: 0000000000000000 RSI: 0000200000000f40 RDI: 0000200000000600
RBP: 00007f618743503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6187626128 R14: 00007f6187626090 R15: 00007ffea84da5d8
</TASK>
Modules linked in:
CR2: fffffffffffffffb
---[ end trace 0000000000000000 ]---
RIP: 0010:hfs_bnode_num_recs_invalid fs/hfsplus/hfsplus_fs.h:605 [inline]
RIP: 0010:__hfsplus_brec_find+0xe0/0x850 fs/hfsplus/bfind.c:114
Code: e8 c5 6f 7f ff 4d 85 ff 74 67 48 89 5c 24 38 4c 89 f8 48 c1 e8 03 48 89 44 24 10 42 80 3c 20 00 74 08 4c 89 ff e8 d0 6c 7f ff <49> 8b 1f 48 85 db 74 4b 4c 89 6c 24 28 48 83 c3 38 48 89 d8 48 c1
RSP: 0018:ffffc9000e93f480 EFLAGS: 00010246
RAX: 1fffffffffffffff RBX: ffffc9000e93f820 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000000000ff RDI: ffffc9000e93f834
RBP: ffffc9000e93f570 R08: ffffc9000e93f833 R09: 0000000000000000
R10: ffffc9000e93f820 R11: fffff52001d27f07 R12: dffffc0000000000
R13: ffffc9000e93f800 R14: 1ffff92001d27e98 R15: fffffffffffffffb
FS: 00007f61883236c0(0000) GS:ffff88808c2ca000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffb CR3: 000000001296f000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: e8 c5 6f 7f ff call 0xff7f6fca
5: 4d 85 ff test %r15,%r15
8: 74 67 je 0x71
a: 48 89 5c 24 38 mov %rbx,0x38(%rsp)
f: 4c 89 f8 mov %r15,%rax
12: 48 c1 e8 03 shr $0x3,%rax
16: 48 89 44 24 10 mov %rax,0x10(%rsp)
1b: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
20: 74 08 je 0x2a
22: 4c 89 ff mov %r15,%rdi
25: e8 d0 6c 7f ff call 0xff7f6cfa
* 2a: 49 8b 1f mov (%r15),%rbx <-- trapping instruction
2d: 48 85 db test %rbx,%rbx
30: 74 4b je 0x7d
32: 4c 89 6c 24 28 mov %r13,0x28(%rsp)
37: 48 83 c3 38 add $0x38,%rbx
3b: 48 89 d8 mov %rbx,%rax
3e: 48 rex.W
3f: c1 .byte 0xc1
* Struck through repros no longer work on HEAD.