[syzbot] [fs?] WARNING in nsproxy_ns_active_get

[syzbot] [fs?] WARNING in nsproxy_ns_active_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    17490bd0527f Add linux-next specific files for 20251104
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1006532f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9995c0d2611ab121
dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1406532f980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1166ff34580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a4d318147846/disk-17490bd0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/86641a470170/vmlinux-17490bd0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/35c008a540c8/bzImage-17490bd0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:288 at __ns_ref_active_get include/linux/ns_common.h:288 [inline], CPU#1: syz.0.20/6007
WARNING: ./include/linux/ns_common.h:288 at nsproxy_ns_active_get+0x8ab/0xcb0 fs/nsfs.c:690, CPU#1: syz.0.20/6007
Modules linked in:
CPU: 1 UID: 0 PID: 6007 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ns_ref_active_get include/linux/ns_common.h:288 [inline]
RIP: 0010:nsproxy_ns_active_get+0x8ab/0xcb0 fs/nsfs.c:690
Code: 5f 5d e9 08 ca 18 09 cc e8 32 8c 77 ff 90 0f 0b 90 e9 ee f7 ff ff e8 24 8c 77 ff 90 0f 0b 90 e9 12 f8 ff ff e8 16 8c 77 ff 90 <0f> 0b 90 e9 dc f8 ff ff e8 08 8c 77 ff 90 0f 0b 90 e9 03 f9 ff ff
RSP: 0018:ffffc900039cfd40 EFLAGS: 00010293
RAX: ffffffff8249d07a RBX: ffff8880582bb680 RCX: ffff88806aeb5b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00000000f0000301 R08: ffff88807ca21913 R09: 1ffff1100f944322
R10: dffffc0000000000 R11: ffffed100f944323 R12: dffffc0000000000
R13: 1ffff1100d52d683 R14: ffff88807ca21910 R15: ffff88807ca216c0
FS:  0000555570bd2500(0000) GS:ffff888125b92000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30163fff CR3: 000000007d256000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 switch_task_namespaces+0x3e/0x110 kernel/nsproxy.c:240
 commit_nsset kernel/nsproxy.c:555 [inline]
 __do_sys_setns kernel/nsproxy.c:591 [inline]
 __se_sys_setns+0x784/0x17d0 kernel/nsproxy.c:559
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc583f8f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd2014d848 EFLAGS: 00000246 ORIG_RAX: 0000000000000134
RAX: ffffffffffffffda RBX: 00007fc5841e5fa0 RCX: 00007fc583f8f6c9
RDX: 0000000000000000 RSI: 0000000024020000 RDI: 0000000000000003
RBP: 00007fc584011f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5841e5fa0 R14: 00007fc5841e5fa0 R15: 0000000000000002
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Forwarded: [PATCH] nsfs: skip active reference management on initial namespaces

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] nsfs: skip active reference management on initial namespaces
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

Initial namespaces (init_net, init_uts_ns, init_pid_ns, etc.) are
statically allocated and exist for the entire lifetime of the system.
They should not participate in active reference counting.

When operations involve initial namespaces, both ns_ref_active_get()
and ns_ref_active_put() were managing active references on them.
This caused the active reference count to become imbalanced, leading
to warnings in __ns_ref_active_get() and __ns_ref_active_put().

Fix by adding is_initial_namespace() checks in both the
ns_ref_active_get and ns_ref_active_put macros. Initial namespaces
are now completely excluded from active reference management,
treating them as permanent kernel resources.

Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 include/linux/ns_common.h | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index bd4492ef6ffc..b22c692b5f38 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -289,7 +289,10 @@ static __always_inline void __ns_ref_active_get(struct ns_common *ns)
 	VFS_WARN_ON_ONCE(is_initial_namespace(ns) && __ns_ref_active_read(ns) <= 0);
 }
 #define ns_ref_active_get(__ns) \
-	do { if (__ns) __ns_ref_active_get(to_ns_common(__ns)); } while (0)
+	do { \
+		if ((__ns) && !is_initial_namespace(&(__ns)->ns)) \
+			__ns_ref_active_get(to_ns_common(__ns)); \
+	} while (0)
 
 static __always_inline bool __ns_ref_active_get_not_zero(struct ns_common *ns)
 {
@@ -314,7 +317,10 @@ static __always_inline void __ns_ref_active_put(struct ns_common *ns)
 	}
 }
 #define ns_ref_active_put(__ns) \
-	do { if (__ns) __ns_ref_active_put(to_ns_common(__ns)); } while (0)
+	do { \
+		if ((__ns) && !is_initial_namespace(&(__ns)->ns)) \
+			__ns_ref_active_put(to_ns_common(__ns)); \
+	} while (0)
 
 static __always_inline struct ns_common *__must_check ns_get_unless_inactive(struct ns_common *ns)
 {
-- 
2.43.0

Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_get

[Christian Brauner]

On Wed, Nov 05, 2025 at 05:35:28PM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    17490bd0527f Add linux-next specific files for 20251104
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1006532f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=9995c0d2611ab121
> dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1406532f980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1166ff34580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/a4d318147846/disk-17490bd0.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/86641a470170/vmlinux-17490bd0.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/35c008a540c8/bzImage-17490bd0.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com

#syz test: https://github.com/brauner/linux.git namespace-6.19

Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_get

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in __ns_ref_active_put

------------[ cut here ]------------
WARNING: CPU: 0 PID: 6510 at kernel/nscommon.c:171 __ns_ref_active_put+0x3d7/0x450 kernel/nscommon.c:171
Modules linked in:
CPU: 0 UID: 0 PID: 6510 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ns_ref_active_put+0x3d7/0x450 kernel/nscommon.c:171
Code: 4d 8b 3e e9 1b fd ff ff e8 76 62 32 00 90 0f 0b 90 e9 29 fd ff ff e8 68 62 32 00 90 0f 0b 90 e9 59 fd ff ff e8 5a 62 32 00 90 <0f> 0b 90 e9 72 ff ff ff e8 4c 62 32 00 90 0f 0b 90 e9 64 ff ff ff
RSP: 0018:ffffc900038dfa60 EFLAGS: 00010293
RAX: ffffffff818e5946 RBX: 00000000ffffffff RCX: ffff88802f641e40
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000000
RBP: ffffc900038dfc00 R08: ffff88807dbaac6b R09: 1ffff1100fb7558d
R10: dffffc0000000000 R11: ffffed100fb7558e R12: dffffc0000000000
R13: 1ffff1100fb7558c R14: ffff88807dbaac60 R15: ffff88807dbaac68
FS:  0000000000000000(0000) GS:ffff888125cf3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555674424a8 CR3: 000000000df38000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 nsproxy_ns_active_put+0x87/0x200 fs/nsfs.c:702
 free_nsproxy kernel/nsproxy.c:80 [inline]
 put_nsproxy include/linux/nsproxy.h:110 [inline]
 switch_task_namespaces+0xc2/0x120 kernel/nsproxy.c:223
 do_exit+0x6b0/0x2300 kernel/exit.c:966
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efc6318f6c9
Code: Unable to access opcode bytes at 0x7efc6318f69f.
RSP: 002b:00007efc63f910e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007efc633e5fa8 RCX: 00007efc6318f6c9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efc633e5fa8
RBP: 00007efc633e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efc633e6038 R14: 00007fff3109d6b0 R15: 00007fff3109d798
 </TASK>


Tested on:

commit:         cc719c88 nsproxy: fix free_nsproxy() and simplify crea..
git tree:       https://github.com/brauner/linux.git namespace-6.19
console output: https://syzkaller.appspot.com/x/log.txt?x=147c8658580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59952e73920025e4
dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Note: no patches were applied.

Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_get

[Christian Brauner]

On Tue, Nov 11, 2025 at 05:54:02AM -0800, syzbot wrote:
> Hello,
> 
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> WARNING in __ns_ref_active_put
> 
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 6510 at kernel/nscommon.c:171 __ns_ref_active_put+0x3d7/0x450 kernel/nscommon.c:171
> Modules linked in:
> CPU: 0 UID: 0 PID: 6510 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> RIP: 0010:__ns_ref_active_put+0x3d7/0x450 kernel/nscommon.c:171
> Code: 4d 8b 3e e9 1b fd ff ff e8 76 62 32 00 90 0f 0b 90 e9 29 fd ff ff e8 68 62 32 00 90 0f 0b 90 e9 59 fd ff ff e8 5a 62 32 00 90 <0f> 0b 90 e9 72 ff ff ff e8 4c 62 32 00 90 0f 0b 90 e9 64 ff ff ff
> RSP: 0018:ffffc900038dfa60 EFLAGS: 00010293
> RAX: ffffffff818e5946 RBX: 00000000ffffffff RCX: ffff88802f641e40
> RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000000
> RBP: ffffc900038dfc00 R08: ffff88807dbaac6b R09: 1ffff1100fb7558d
> R10: dffffc0000000000 R11: ffffed100fb7558e R12: dffffc0000000000
> R13: 1ffff1100fb7558c R14: ffff88807dbaac60 R15: ffff88807dbaac68
> FS:  0000000000000000(0000) GS:ffff888125cf3000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00005555674424a8 CR3: 000000000df38000 CR4: 00000000003526f0
> Call Trace:
>  <TASK>
>  nsproxy_ns_active_put+0x87/0x200 fs/nsfs.c:702
>  free_nsproxy kernel/nsproxy.c:80 [inline]
>  put_nsproxy include/linux/nsproxy.h:110 [inline]
>  switch_task_namespaces+0xc2/0x120 kernel/nsproxy.c:223
>  do_exit+0x6b0/0x2300 kernel/exit.c:966
>  do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
>  get_signal+0x1285/0x1340 kernel/signal.c:3034
>  arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
>  exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
>  exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
>  syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
>  syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
>  do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7efc6318f6c9
> Code: Unable to access opcode bytes at 0x7efc6318f69f.
> RSP: 002b:00007efc63f910e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
> RAX: fffffffffffffe00 RBX: 00007efc633e5fa8 RCX: 00007efc6318f6c9
> RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efc633e5fa8
> RBP: 00007efc633e5fa0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007efc633e6038 R14: 00007fff3109d6b0 R15: 00007fff3109d798
>  </TASK>
> 
> 
> Tested on:
> 
> commit:         cc719c88 nsproxy: fix free_nsproxy() and simplify crea..
> git tree:       https://github.com/brauner/linux.git namespace-6.19
> console output: https://syzkaller.appspot.com/x/log.txt?x=147c8658580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=59952e73920025e4
> dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> 
> Note: no patches were applied.

#syz test: https://github.com/brauner/linux.git namespace-6.19

Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_get

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com
Tested-by: syzbot+0a8655a80e189278487e@syzkaller.appspotmail.com

Tested on:

commit:         53974b87 nsproxy: fix free_nsproxy() and simplify crea..
git tree:       https://github.com/brauner/linux.git namespace-6.19
console output: https://syzkaller.appspot.com/x/log.txt?x=143dec12580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59952e73920025e4
dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [fs?] WARNING in nsproxy_ns_active_get

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

3.654920][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 2b1e50eda567f48aae3b59ba5ce868b06b486d7e'
[   23.982352][    T1] zswap: loaded using pool 842
[   23.991410][    T1] Demotion targets for Node 0: null
[   23.996985][    T1] Demotion targets for Node 1: null
[   24.002328][    T1] debug_vm_pgtable: [debug_vm_pgtable         ]: Validating architecture page table helpers
[   26.824926][    T1] Key type .fscrypt registered
[   26.829883][    T1] Key type fscrypt-provisioning registered
[   26.839281][    T1] kAFS: Red Hat AFS client v0.1 registering.
[   26.865411][    T1] Btrfs loaded, assert=on, zoned=yes, fsverity=yes
[   26.872528][    T1] Key type big_key registered
[   26.877283][    T1] Key type encrypted registered
[   26.882161][    T1] AppArmor: AppArmor sha256 policy hashing enabled
[   26.888954][    T1] ima: No TPM chip found, activating TPM-bypass!
[   26.895372][    T1] Loading compiled-in module X.509 certificates
[   26.922050][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 2b1e50eda567f48aae3b59ba5ce868b06b486d7e'
[   26.932919][    T1] ima: Allocated hash algorithm: sha256
[   26.938925][    T1] ima: No architecture policies found
[   26.944865][    T1] evm: Initialising EVM extended attributes:
[   26.950942][    T1] evm: security.selinux (disabled)
[   26.956088][    T1] evm: security.SMACK64 (disabled)
[   26.961183][    T1] evm: security.SMACK64EXEC (disabled)
[   26.966630][    T1] evm: security.SMACK64TRANSMUTE (disabled)
[   26.972527][    T1] evm: security.SMACK64MMAP (disabled)
[   26.978060][    T1] evm: security.apparmor
[   26.982473][    T1] evm: security.ima
[   26.986261][    T1] evm: security.capability
[   26.990651][    T1] evm: HMAC attrs: 0x1
[   26.997017][    T1] PM:   Magic number: 1:107:131
[   27.002026][    T1] video4linux video31: hash matches
[   27.007554][    T1] block nbd10: hash matches
[   27.012543][    T1] acpi device:06: hash matches
[   27.017647][    T1] netconsole: network logging started
[   27.023759][    T1] gtp: GTP module loaded (pdp ctx size 128 bytes)
[   27.035896][    T1] rdma_rxe: loaded
[   27.041816][    T1] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   27.052989][    T1] Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   27.060977][    T1] Loaded X.509 cert 'wens: 61c038651aabdcf94bd0ac7ff06c7248db18c600'
[   27.072219][    T1] clk: Disabling unused clocks
[   27.073861][   T63] faux_driver regulatory: Direct firmware load for regulatory.db failed with error -2
[   27.077172][    T1] ALSA device list:
[   27.087180][   T63] faux_driver regulatory: Falling back to sysfs fallback for: regulatory.db
[   27.090785][    T1]   #0: Dummy 1
[   27.103854][    T1]   #1: Loopback 1
[   27.107903][    T1]   #2: Virtual MIDI Card 1
[   27.115574][    T1] check access for rdinit=/init failed: -2, ignoring
[   27.122507][    T1] md: Waiting for all devices to be available before autodetect
[   27.130224][    T1] md: If you don't use raid, use raid=noautodetect
[   27.136785][    T1] md: Autodetecting RAID arrays.
[   27.141856][    T1] md: autorun ...
[   27.145572][    T1] md: ... autorun DONE.
[   27.254350][    T1] EXT4-fs (sda1): orphan cleanup on readonly fs
[   27.262975][    T1] EXT4-fs (sda1): mounted filesystem 4f91c6db-4997-4bb4-91b8-7e83a20c1bf1 ro with ordered data mode. Quota mode: none.
[   27.275897][    T1] VFS: Mounted root (ext4 filesystem) readonly on device 8:1.
[   27.285690][    T1] devtmpfs: mounted
[   27.362347][    T1] Freeing unused kernel image (initmem) memory: 26112K
[   27.373258][    T1] Write protecting the kernel read-only data: 212992k
[   27.392412][    T1] Freeing unused kernel image (text/rodata gap) memory: 1436K
[   27.405281][    T1] Freeing unused kernel image (rodata/data gap) memory: 1240K
[   27.510532][    T1] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[   27.518752][    T1] x86/mm: Checking user space page tables
[   27.608528][    T1] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[   27.622261][    T1] Failed to set sysctl parameter 'max_rcu_stall_to_panic=1': parameter not found
[   27.632373][    T1] Run /sbin/init as init process
[   27.899076][ T5159] mount (5159) used greatest stack depth: 23624 bytes left
[   27.967399][ T5160] EXT4-fs (sda1): re-mounted 4f91c6db-4997-4bb4-91b8-7e83a20c1bf1 r/w.
mount: mounting devtmpfs on /dev failed: Device or resource busy
mount: mounting smackfs on /sys/fs/smackfs failed: No such file or directory
mount: mounting selinuxfs on /sys/fs/selinux failed: No such file or directory
[   28.105113][ T5164] mount (5164) used greatest stack depth: 21672 bytes left
Starting syslogd: OK
Starting acpid: OK
Starting klogd: OK
Running sysctl: OK
Populating /dev using udev: [   29.176871][ T5194] udevd[5194]: starting version 3.2.14
[   29.365166][ T5195] udevd[5195]: starting eudev-3.2.14
[   29.367815][ T5194] udevd (5194) used greatest stack depth: 18696 bytes left
done
Starting system message bus: done
Starting iptables: OK
Starting network: OK
Starting dhcpcd...
dhcpcd-10.2.0 starting
[   49.444742][ T5489] ------------[ cut here ]------------
[   49.450246][ T5489] WARNING: ./include/linux/ns_common.h:314 at nsfs_evict+0x18e/0x200, CPU#1: dhcpcd/5489
[   49.461849][ T5489] Modules linked in:
[   49.465873][ T5489] CPU: 1 UID: 0 PID: 5489 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
[   49.475268][ T5489] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[   49.485891][ T5489] RIP: 0010:nsfs_evict+0x18e/0x200
[   49.491026][ T5489] Code: 4d 8b 1e 48 89 df 5b 41 5c 41 5d 41 5e 41 5f 5d 41 ff e3 cc cc cc e8 01 c7 76 ff 90 0f 0b 90 e9 1f ff ff ff e8 f3 c6 76 ff 90 <0f> 0b 90 e9 42 ff ff ff e8 e5 c6 76 ff 90 0f 0b 90 e9 72 ff ff ff
[   49.511222][ T5489] RSP: 0018:ffffc90003adfa28 EFLAGS: 00010293
[   49.517709][ T5489] RAX: ffffffff824b0e3d RBX: ffffffff9a180fd8 RCX: ffff88802f9f5b80
[   49.526255][ T5489] RDX: 0000000000000000 RSI: 00000000effffff8 RDI: 00000000effffff8
[   49.535159][ T5489] RBP: 00000000effffff8 R08: ffffffff9a181093 R09: 1ffffffff3430212
[   49.543377][ T5489] R10: dffffc0000000000 R11: fffffbfff3430213 R12: dffffc0000000000
[   49.551608][ T5489] R13: 1ffffffff34301fe R14: ffff88807a78f740 R15: ffffffff9a180ff0
[   49.559609][ T5489] FS:  00007f34c5e7d740(0000) GS:ffff888125b78000(0000) knlGS:0000000000000000
[   49.568761][ T5489] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   49.575391][ T5489] CR2: 000055fd54bd54a0 CR3: 0000000050a6a000 CR4: 00000000003526f0
[   49.583450][ T5489] Call Trace:
[   49.586856][ T5489]  <TASK>
[   49.589790][ T5489]  ? __pfx_nsfs_evict+0x10/0x10
[   49.594786][ T5489]  evict+0x5f4/0xae0
[   49.598708][ T5489]  ? __pfx_evict+0x10/0x10
[   49.603192][ T5489]  ? _raw_spin_unlock+0x28/0x50
[   49.608075][ T5489]  ? iput+0xce7/0x1050
[   49.612199][ T5489]  __dentry_kill+0x209/0x660
[   49.616894][ T5489]  ? dput+0x37/0x2b0
[   49.620853][ T5489]  dput+0x19f/0x2b0
[   49.625240][ T5489]  path_put+0x39/0x60
[   49.629332][ T5489]  vfs_statx+0x36e/0x550
[   49.633784][ T5489]  ? __pfx_vfs_statx+0x10/0x10
[   49.638565][ T5489]  ? strncpy_from_user+0x150/0x2c0
[   49.643871][ T5489]  ? getname_flags+0x1e5/0x540
[   49.648659][ T5489]  vfs_fstatat+0x118/0x170
[   49.653220][ T5489]  __x64_sys_newfstatat+0x116/0x190
[   49.658872][ T5489]  ? __pfx___x64_sys_newfstatat+0x10/0x10
[   49.664675][ T5489]  ? do_syscall_64+0xbe/0xfa0
[   49.669371][ T5489]  do_syscall_64+0xfa/0xfa0
[   49.674260][ T5489]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   49.680359][ T5489]  ? clear_bhb_loop+0x60/0xb0
[   49.685201][ T5489]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   49.691150][ T5489] RIP: 0033:0x7f34c5f71b0a
[   49.695754][ T5489] Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
[   49.715431][ T5489] RSP: 002b:00007ffd494b4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
[   49.724018][ T5489] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f34c5f71b0a
[   49.732166][ T5489] RDX: 00007ffd494b4030 RSI: 000055fd54bfd557 RDI: 00000000ffffff9c
[   49.740133][ T5489] RBP: 00007ffd494b67c8 R08: 0000000000000000 R09: 0000000000000000
[   49.748181][ T5489] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd494b51a0
[   49.756207][ T5489] R13: 000055fd7bac88a0 R14: 0000000000001000 R15: 00007f34c5e7d6c8
[   49.764232][ T5489]  </TASK>
[   49.767259][ T5489] Kernel panic - not syncing: kernel: panic_on_warn set ...
[   49.774523][ T5489] CPU: 1 UID: 0 PID: 5489 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
[   49.783536][ T5489] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[   49.793664][ T5489] Call Trace:
[   49.796937][ T5489]  <TASK>
[   49.799886][ T5489]  dump_stack_lvl+0x99/0x250
[   49.804503][ T5489]  ? __asan_memcpy+0x40/0x70
[   49.809232][ T5489]  ? __pfx_dump_stack_lvl+0x10/0x10
[   49.814434][ T5489]  ? __pfx__printk+0x10/0x10
[   49.819062][ T5489]  vpanic+0x237/0x6d0
[   49.823042][ T5489]  ? __pfx_vpanic+0x10/0x10
[   49.827540][ T5489]  ? is_bpf_text_address+0x292/0x2b0
[   49.832910][ T5489]  ? is_bpf_text_address+0x26/0x2b0
[   49.838109][ T5489]  panic+0xb9/0xc0
[   49.841907][ T5489]  ? __pfx_panic+0x10/0x10
[   49.846325][ T5489]  __warn+0x334/0x4c0
[   49.850307][ T5489]  ? nsfs_evict+0x18e/0x200
[   49.854809][ T5489]  ? nsfs_evict+0x18e/0x200
[   49.859319][ T5489]  report_bug+0x2be/0x4f0
[   49.863803][ T5489]  ? nsfs_evict+0x18e/0x200
[   49.868590][ T5489]  ? nsfs_evict+0x18e/0x200
[   49.873445][ T5489]  ? nsfs_evict+0x190/0x200
[   49.877981][ T5489]  handle_bug+0x84/0x160
[   49.882217][ T5489]  exc_invalid_op+0x1a/0x50
[   49.886826][ T5489]  asm_exc_invalid_op+0x1a/0x20
[   49.891681][ T5489] RIP: 0010:nsfs_evict+0x18e/0x200
[   49.896878][ T5489] Code: 4d 8b 1e 48 89 df 5b 41 5c 41 5d 41 5e 41 5f 5d 41 ff e3 cc cc cc e8 01 c7 76 ff 90 0f 0b 90 e9 1f ff ff ff e8 f3 c6 76 ff 90 <0f> 0b 90 e9 42 ff ff ff e8 e5 c6 76 ff 90 0f 0b 90 e9 72 ff ff ff
[   49.916792][ T5489] RSP: 0018:ffffc90003adfa28 EFLAGS: 00010293
[   49.922856][ T5489] RAX: ffffffff824b0e3d RBX: ffffffff9a180fd8 RCX: ffff88802f9f5b80
[   49.930820][ T5489] RDX: 0000000000000000 RSI: 00000000effffff8 RDI: 00000000effffff8
[   49.938872][ T5489] RBP: 00000000effffff8 R08: ffffffff9a181093 R09: 1ffffffff3430212
[   49.947351][ T5489] R10: dffffc0000000000 R11: fffffbfff3430213 R12: dffffc0000000000
[   49.955403][ T5489] R13: 1ffffffff34301fe R14: ffff88807a78f740 R15: ffffffff9a180ff0
[   49.963463][ T5489]  ? nsfs_evict+0x18d/0x200
[   49.969170][ T5489]  ? nsfs_evict+0x18d/0x200
[   49.973769][ T5489]  ? __pfx_nsfs_evict+0x10/0x10
[   49.978624][ T5489]  evict+0x5f4/0xae0
[   49.982525][ T5489]  ? __pfx_evict+0x10/0x10
[   49.986950][ T5489]  ? _raw_spin_unlock+0x28/0x50
[   49.992068][ T5489]  ? iput+0xce7/0x1050
[   49.996224][ T5489]  __dentry_kill+0x209/0x660
[   50.000806][ T5489]  ? dput+0x37/0x2b0
[   50.004864][ T5489]  dput+0x19f/0x2b0
[   50.008661][ T5489]  path_put+0x39/0x60
[   50.012634][ T5489]  vfs_statx+0x36e/0x550
[   50.016905][ T5489]  ? __pfx_vfs_statx+0x10/0x10
[   50.021714][ T5489]  ? strncpy_from_user+0x150/0x2c0
[   50.026926][ T5489]  ? getname_flags+0x1e5/0x540
[   50.031689][ T5489]  vfs_fstatat+0x118/0x170
[   50.036099][ T5489]  __x64_sys_newfstatat+0x116/0x190
[   50.041293][ T5489]  ? __pfx___x64_sys_newfstatat+0x10/0x10
[   50.047113][ T5489]  ? do_syscall_64+0xbe/0xfa0
[   50.051797][ T5489]  do_syscall_64+0xfa/0xfa0
[   50.056316][ T5489]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   50.062385][ T5489]  ? clear_bhb_loop+0x60/0xb0
[   50.067083][ T5489]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   50.072967][ T5489] RIP: 0033:0x7f34c5f71b0a
[   50.077370][ T5489] Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
[   50.096988][ T5489] RSP: 002b:00007ffd494b4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
[   50.105404][ T5489] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f34c5f71b0a
[   50.113378][ T5489] RDX: 00007ffd494b4030 RSI: 000055fd54bfd557 RDI: 00000000ffffff9c
[   50.121341][ T5489] RBP: 00007ffd494b67c8 R08: 0000000000000000 R09: 0000000000000000
[   50.129389][ T5489] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd494b51a0
[   50.137355][ T5489] R13: 000055fd7bac88a0 R14: 0000000000001000 R15: 00007f34c5e7d6c8
[   50.145417][ T5489]  </TASK>
[   50.148770][ T5489] Kernel Offset: disabled
[   50.153141][ T5489] Rebooting in 86400 seconds..


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3406885182=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at a6c9c731229
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=a6c9c7312290da5bca2fc1be4872a7aeefb6e3ea -X github.com/google/syzkaller/prog.gitRevisionDate=20251104-181356"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=a6c9c7312290da5bca2fc1be4872a7aeefb6e3ea -X github.com/google/syzkaller/prog.gitRevisionDate=20251104-181356"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=a6c9c7312290da5bca2fc1be4872a7aeefb6e3ea -X github.com/google/syzkaller/prog.gitRevisionDate=20251104-181356"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"a6c9c7312290da5bca2fc1be4872a7aeefb6e3ea\"
/usr/bin/ld: /tmp/cc7wkuO8.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x104): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=12e510b4580000


Tested on:

commit:         9c0826a5 Add linux-next specific files for 20251107
git tree:       linux-next
kernel config:  https://syzkaller.appspot.com/x/.config?x=4f8fcc6438a785e7
dashboard link: https://syzkaller.appspot.com/bug?extid=0a8655a80e189278487e
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12c5e17c580000