stack segment fault in kernfs_rename_ns (2)

Status: moderation: reported on 2026/04/16 07:26
Subsystems: kernfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+faeac5b54ba997a96278@syzkaller.appspotmail.com
First crash: 117d, last: 4d19h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
13d73f4e assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ✅ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ stack segment fault in kernfs_rename_ns (2) 2026/05/26 11:25 2026/05/26 11:25 2026/05/26 12:41 c69befb3
Discussions (1)
Title Replies (including bot) Last reply
[PATCH] sysfs: return -ENOENT from move/rename when kobj->sd is NULL 5 (5) 2026/05/04 20:55
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream stack segment fault in kernfs_rename_ns bluetooth 2 35 199d 383d 0/29 auto-obsoleted due to no activity on 2026/04/10 15:40

Sample crash report:
ipt_ECN: cannot use operation on non-tcp rule
Oops: stack segment: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 23826 Comm: syz.3.4689 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kernfs_rename_ns+0x3a/0x800 fs/kernfs/dir.c:1828
Code: ec 38 48 89 cb 48 89 54 24 10 49 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 b1 00 52 ff 4d 8d 7e 30 4c 89 fd 48 c1 ed 03 <42> 80 7c 25 00 00 74 08 4c 89 ff e8 f6 97 bf ff 49 83 3f 00 0f 84
RSP: 0018:ffffc90004aff930 EFLAGS: 00010206
RAX: ffffffff8275134f RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000e07b000 RSI: 0000000000000fbc RDI: 0000000000000fbd
RBP: 0000000000000006 R08: ffff88805538be00 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000002 R12: dffffc0000000000
R13: ffff8880236e7c30 R14: 0000000000000000 R15: 0000000000000030
FS:  00007f76827256c0(0000) GS:ffff88812504d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6f395eb700 CR3: 000000007a9a0000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kobject_move+0x560/0x720 lib/kobject.c:569
 device_move+0xe0/0x720 drivers/base/core.c:4689
 hci_conn_del_sysfs+0xb8/0x1a0 net/bluetooth/hci_sysfs.c:75
 hci_conn_cleanup net/bluetooth/hci_conn.c:170 [inline]
 hci_conn_del+0xc3d/0x1200 net/bluetooth/hci_conn.c:1308
 hci_conn_hash_flush+0x189/0x260 net/bluetooth/hci_conn.c:2736
 hci_dev_close_sync+0x7fc/0x10a0 net/bluetooth/hci_sync.c:5513
 hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
 hci_dev_close+0x108/0x260 net/bluetooth/hci_core.c:524
 sock_do_ioctl+0x101/0x320 net/socket.c:1300
 sock_ioctl+0x57a/0x7e0 net/socket.c:1421
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f768179e019
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:00007f7682725028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7681a25fa0 RCX: 00007f768179e019
RDX: 0000200000000000 RSI: 00000000400448ca RDI: 0000000000000004
RBP: 00007f768183500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7681a26038 R14: 00007f7681a25fa0 R15: 00007ffcc69ff328
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:kernfs_rename_ns+0x3a/0x800 fs/kernfs/dir.c:1828
Code: ec 38 48 89 cb 48 89 54 24 10 49 89 f5 49 89 fe 49 bc 00 00 00 00 00 fc ff df e8 b1 00 52 ff 4d 8d 7e 30 4c 89 fd 48 c1 ed 03 <42> 80 7c 25 00 00 74 08 4c 89 ff e8 f6 97 bf ff 49 83 3f 00 0f 84
RSP: 0018:ffffc90004aff930 EFLAGS: 00010206
RAX: ffffffff8275134f RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000e07b000 RSI: 0000000000000fbc RDI: 0000000000000fbd
RBP: 0000000000000006 R08: ffff88805538be00 R09: 0000000000000008
R10: 0000000000000007 R11: 0000000000000002 R12: dffffc0000000000
R13: ffff8880236e7c30 R14: 0000000000000000 R15: 0000000000000030
FS:  00007f76827256c0(0000) GS:ffff88812504d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3ac864 CR3: 000000007a9a0000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	ec                   	in     (%dx),%al
   1:	38 48 89             	cmp    %cl,-0x77(%rax)
   4:	cb                   	lret
   5:	48 89 54 24 10       	mov    %rdx,0x10(%rsp)
   a:	49 89 f5             	mov    %rsi,%r13
   d:	49 89 fe             	mov    %rdi,%r14
  10:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  17:	fc ff df
  1a:	e8 b1 00 52 ff       	call   0xff5200d0
  1f:	4d 8d 7e 30          	lea    0x30(%r14),%r15
  23:	4c 89 fd             	mov    %r15,%rbp
  26:	48 c1 ed 03          	shr    $0x3,%rbp
* 2a:	42 80 7c 25 00 00    	cmpb   $0x0,0x0(%rbp,%r12,1) <-- trapping instruction
  30:	74 08                	je     0x3a
  32:	4c 89 ff             	mov    %r15,%rdi
  35:	e8 f6 97 bf ff       	call   0xffbf9830
  3a:	49 83 3f 00          	cmpq   $0x0,(%r15)
  3e:	0f                   	.byte 0xf
  3f:	84                   	.byte 0x84

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/02 18:21 net af39eb111ce6 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce stack segment fault in kernfs_rename_ns
2026/04/12 07:24 net 02f729643959 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce stack segment fault in kernfs_rename_ns
2026/07/03 13:02 linux-next 6eb8711ece2c 58bf2096 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce stack segment fault in kernfs_rename_ns
* Struck through repros no longer work on HEAD.