syzbot


WARNING in nsproxy_ns_active_put

Status: upstream: reported C repro on 2025/11/06 01:36
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+0b2e79f91ff6579bfa5b@syzkaller.appspotmail.com
Fix commit: cefd55bd2159 nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm]
First crash: 47d, last: 39d
Cause bisection: introduced by (bisect log) :
commit 3a18f809184bc5a1cfad7cde5b8b026e2ff61587
Author: Christian Brauner <brauner@kernel.org>
Date: Wed Oct 29 12:20:24 2025 +0000

  ns: add active reference count

Crash: WARNING in alloc_pid (log)
Repro: C syz .config
  
Discussions (4)
Title Replies (including bot) Last reply
[PATCH] nsproxy: fix free_nsproxy() and simplify create_new_namespaces() 3 (3) 2025/11/13 13:05
[syzbot] [fs?] WARNING in nsproxy_ns_active_put 5 (16) 2025/11/11 16:14
[PATCH v2] fs/nsfs: skip active ref counting for initial namespaces 2 (2) 2025/11/11 09:27
[PATCH] fs/nsfs: skip dropping active refs on initial namespaces 2 (2) 2025/11/09 09:12
Last patch testing requests (8)
Created Duration User Patch Repo Result
2025/11/11 15:07 25m brauner@kernel.org https://github.com/brauner/linux.git namespace-6.19 OK log
2025/11/11 11:38 1h14m brauner@kernel.org https://github.com/brauner/linux.git namespace-6.19 report log
2025/11/11 10:26 24m brauner@kernel.org https://github.com/brauner/linux.git namespace-6.19.fixes error
2025/11/11 09:24 17m brauner@kernel.org https://github.com/brauner/linux.git namespace-6.19 report log
2025/11/07 11:43 37m kartikey406@gmail.com patch linux-next error
2025/11/07 11:41 35m kartikey406@gmail.com patch linux-next error
2025/11/07 11:16 18m kartikey406@gmail.com patch linux-next report log
2025/11/07 10:14 24m kartikey406@gmail.com patch linux-next report log

Sample crash report:
------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:311 at __ns_ref_active_put include/linux/ns_common.h:311 [inline], CPU#0: syz.0.20/5983
WARNING: ./include/linux/ns_common.h:311 at nsproxy_ns_active_put+0xa19/0xd30 fs/nsfs.c:707, CPU#0: syz.0.20/5983
Modules linked in:
CPU: 0 UID: 0 PID: 5983 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_put include/linux/ns_common.h:311 [inline]
RIP: 0010:nsproxy_ns_active_put+0xa19/0xd30 fs/nsfs.c:707
Code: 0f 0b 90 e9 71 fc ff ff e8 a4 ec 76 ff 90 0f 0b 90 e9 ab fc ff ff e8 96 ec 76 ff 90 0f 0b 90 e9 41 fd ff ff e8 88 ec 76 ff 90 <0f> 0b 90 e9 64 fd ff ff e8 7a ec 76 ff 90 0f 0b 90 e9 98 fd ff ff
RSP: 0018:ffffc9000418fd38 EFLAGS: 00010293
RAX: ffffffff824ae3a8 RBX: ffff88801def9f70 RCX: ffff88807db1db80
RDX: 0000000000000000 RSI: 00000000effffff8 RDI: 00000000effffff8
RBP: 00000000effffff8 R08: ffffffff8e36cbcb R09: 1ffffffff1c6d979
R10: dffffc0000000000 R11: fffffbfff1c6d97a R12: dffffc0000000000
R13: 1ffffffff1c6d965 R14: ffffffff8e36cb00 R15: ffffffff8e36cb28
FS:  0000555573597500(0000) GS:ffff888125a79000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f963fff CR3: 000000003430c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 free_nsproxy+0x26/0x560 kernel/nsproxy.c:190
 put_nsset kernel/nsproxy.c:341 [inline]
 __do_sys_setns kernel/nsproxy.c:594 [inline]
 __se_sys_setns+0x1268/0x17d0 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: 0033:0x7fb0c5990ef7
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 34 01 00 00 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:00007ffe41be1078 EFLAGS: 00000246 ORIG_RAX: 0000000000000134
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fb0c5990ef7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000c9
RBP: 00007fb0c5a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb0c5be5fa0 R14: 00007fb0c5be5fa0 R15: 0000000000000003
 </TASK>

Crashes (38):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/09 05:23 linux-next 9c0826a5d9aa 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/08 20:49 linux-next 9c0826a5d9aa 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/07 21:13 linux-next 9c0826a5d9aa 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/05 23:30 linux-next 84d39fb9d529 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/05 21:57 linux-next 84d39fb9d529 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/05 17:55 linux-next 84d39fb9d529 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/05 14:42 linux-next 84d39fb9d529 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/05 12:30 linux-next 84d39fb9d529 a6c9c731 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/04 19:30 linux-next 17490bd0527f 686bf657 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/10 19:20 linux-next ab40c92c74c6 4e1406b4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/11 20:46 linux-next 2666975a8905 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/11 16:43 linux-next 2666975a8905 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/11 13:55 linux-next 2666975a8905 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/11 13:49 linux-next 2666975a8905 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/11 02:58 linux-next ab40c92c74c6 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/11 02:23 linux-next ab40c92c74c6 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/10 23:44 linux-next ab40c92c74c6 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/10 15:45 linux-next ab40c92c74c6 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/10 09:48 linux-next ab40c92c74c6 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 21:50 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 20:09 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 19:44 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 13:32 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 13:16 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 10:01 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 09:56 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/09 08:25 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/08 21:25 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/08 18:41 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/08 18:19 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in nsproxy_ns_active_put
2025/11/07 22:40 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/07 09:19 linux-next 9c0826a5d9aa 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/07 01:13 linux-next df5d79720b15 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/07 01:12 linux-next df5d79720b15 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/07 00:29 linux-next df5d79720b15 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/06 21:06 linux-next df5d79720b15 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/06 12:38 linux-next df5d79720b15 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
2025/11/06 02:50 linux-next 84d39fb9d529 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in nsproxy_ns_active_put
* Struck through repros no longer work on HEAD.