In the Linux kernel, the following vulnerability has been resolved:

hfs: fix missing hfs_bnode_get() in __hfs_bnode_create

Syzbot found a kernel BUG in hfs_bnode_put():

kernel BUG at fs/hfs/bnode.c:466!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 3634 Comm: kworker/u4:5 Not tainted 6.1.0-rc7-syzkaller-00190-g97ee9d1c1696 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:hfs_bnode_put+0x46f/0x480 fs/hfs/bnode.c:466
Code: 8a 80 ff e9 73 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a0 fe ff ff 48 89 df e8 db 8a 80 ff e9 93 fe ff ff e8 a1 68 2c ff <0f> 0b e8 9a 68 2c ff 0f 0b 0f 1f 84 00 00 00 00 00 55 41 57 41 56
RSP: 0018:ffffc90003b4f258 EFLAGS: 00010293
RAX: ffffffff825e318f RBX: 0000000000000000 RCX: ffff8880739dd7c0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003b4f430 R08: ffffffff825e2d9b R09: ffffed10045157d1
R10: ffffed10045157d1 R11: 1ffff110045157d0 R12: ffff8880228abe80
R13: ffff88807016c000 R14: dffffc0000000000 R15: ffff8880228abe00
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa6ebe88718 CR3: 000000001e93d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
hfs_write_inode+0x1bc/0xb40
write_inode fs/fs-writeback.c:1440 [inline]
__writeback_single_inode+0x4d6/0x670 fs/fs-writeback.c:1652
writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1878
__writeback_inodes_wb+0x125/0x420 fs/fs-writeback.c:1949
wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2054
wb_check_start_all fs/fs-writeback.c:2176 [inline]
wb_do_writeback fs/fs-writeback.c:2202 [inline]
wb_workfn+0x827/0xef0 fs/fs-writeback.c:2235
process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

The BUG_ON() is triggered at here:

/* Dispose of resources used by a node */
void hfs_bnode_put(struct hfs_bnode *node)
{
if (node) {
<skipped>
BUG_ON(!atomic_read(&node->refcnt)); <- we have issue here!!!!
<skipped>
}
}

By tracing the refcnt, I found the node is created by hfs_bmap_alloc()
with refcnt 1. Then the node is used by hfs_btree_write(). There is a
missing of hfs_bnode_get() after find the node. The issue happened in
following path:

<alloc>
hfs_bmap_alloc
hfs_bnode_find
__hfs_bnode_create <- allocate a new node with refcnt 1.
hfs_bnode_put <- decrease the refcnt

<write>
hfs_btree_write
hfs_bnode_find
__hfs_bnode_create
hfs_bnode_findhash <- find the node without refcnt increased.
hfs_bnode_put <- trigger the BUG_ON() since refcnt is 0.

Project Subscriptions

Vendors Products
Linux Kernel Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 10 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Tue, 09 Dec 2025 02:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: hfs: fix missing hfs_bnode_get() in __hfs_bnode_create Syzbot found a kernel BUG in hfs_bnode_put(): kernel BUG at fs/hfs/bnode.c:466! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3634 Comm: kworker/u4:5 Not tainted 6.1.0-rc7-syzkaller-00190-g97ee9d1c1696 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: writeback wb_workfn (flush-7:0) RIP: 0010:hfs_bnode_put+0x46f/0x480 fs/hfs/bnode.c:466 Code: 8a 80 ff e9 73 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c a0 fe ff ff 48 89 df e8 db 8a 80 ff e9 93 fe ff ff e8 a1 68 2c ff <0f> 0b e8 9a 68 2c ff 0f 0b 0f 1f 84 00 00 00 00 00 55 41 57 41 56 RSP: 0018:ffffc90003b4f258 EFLAGS: 00010293 RAX: ffffffff825e318f RBX: 0000000000000000 RCX: ffff8880739dd7c0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003b4f430 R08: ffffffff825e2d9b R09: ffffed10045157d1 R10: ffffed10045157d1 R11: 1ffff110045157d0 R12: ffff8880228abe80 R13: ffff88807016c000 R14: dffffc0000000000 R15: ffff8880228abe00 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa6ebe88718 CR3: 000000001e93d000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> hfs_write_inode+0x1bc/0xb40 write_inode fs/fs-writeback.c:1440 [inline] __writeback_single_inode+0x4d6/0x670 fs/fs-writeback.c:1652 writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1878 __writeback_inodes_wb+0x125/0x420 fs/fs-writeback.c:1949 wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2054 wb_check_start_all fs/fs-writeback.c:2176 [inline] wb_do_writeback fs/fs-writeback.c:2202 [inline] wb_workfn+0x827/0xef0 fs/fs-writeback.c:2235 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> The BUG_ON() is triggered at here: /* Dispose of resources used by a node */ void hfs_bnode_put(struct hfs_bnode *node) { if (node) { <skipped> BUG_ON(!atomic_read(&node->refcnt)); <- we have issue here!!!! <skipped> } } By tracing the refcnt, I found the node is created by hfs_bmap_alloc() with refcnt 1. Then the node is used by hfs_btree_write(). There is a missing of hfs_bnode_get() after find the node. The issue happened in following path: <alloc> hfs_bmap_alloc hfs_bnode_find __hfs_bnode_create <- allocate a new node with refcnt 1. hfs_bnode_put <- decrease the refcnt <write> hfs_btree_write hfs_bnode_find __hfs_bnode_create hfs_bnode_findhash <- find the node without refcnt increased. hfs_bnode_put <- trigger the BUG_ON() since refcnt is 0.
Title hfs: fix missing hfs_bnode_get() in __hfs_bnode_create
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-01-05T10:33:06.625Z

Reserved: 2025-12-09T01:27:17.829Z

Link: CVE-2023-53862

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-09T16:17:26.970

Modified: 2025-12-09T18:37:13.640

Link: CVE-2023-53862

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-09T00:00:00Z

Links: CVE-2023-53862 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.