------------[ cut here ]------------ WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#1: ksoftirqd/1/23 WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#1: ksoftirqd/1/23 WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#1: ksoftirqd/1/23 Modules linked in: CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:__ns_ref_put include/linux/ns_common.h:255 [inline] RIP: 0010:put_user_ns include/linux/user_namespace.h:189 [inline] RIP: 0010:put_cred_rcu+0x2c5/0x340 kernel/cred.c:61 Code: 5c 41 5d 41 5e 41 5f 5d e9 48 e1 8d 00 e8 03 8c 32 00 4c 89 e7 be 03 00 00 00 e8 d6 27 00 03 e9 b8 fe ff ff e8 ec 8b 32 00 90 <0f> 0b 90 eb 9f e8 e1 8b 32 00 4c 89 ff be 03 00 00 00 e8 b4 27 00 RSP: 0018:ffffc90000a08ba8 EFLAGS: 00010246 RAX: ffffffff818e8124 RBX: ffff88802f4456a0 RCX: ffff88801ceddb80 RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 0000000000000004 R08: ffff88805711c193 R09: 1ffff1100ae23832 R10: dffffc0000000000 R11: ffffed100ae23833 R12: dffffc0000000000 R13: ffff88802f445600 R14: ffff88805711c000 R15: ffff88805711c190 FS: 0000000000000000(0000) GS:ffff888125fcd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000111030 CR3: 00000000322f4000 CR4: 00000000003526f0 Call Trace: rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 common_interrupt+0xbb/0xe0 arch/x86/kernel/irq.c:318 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 RIP: 0010:finish_task_switch+0x26b/0x960 kernel/sched/core.c:5118 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 2f 05 00 00 4c 8b 75 d0 4c 89 e7 e8 3f 6c c9 09 e8 0a 3e 37 00 fb 4c 8b 65 c0 <49> 8d bc 24 60 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc900001d79d8 EFLAGS: 00000286 RAX: c50056e104b97a00 RBX: 0000000000000000 RCX: c50056e104b97a00 RDX: 0000000000000000 RSI: ffffffff8d787b5c RDI: ffffffff8bbf40e0 RBP: ffffc900001d7a30 R08: ffffffff8f7dc877 R09: 1ffffffff1efb90e R10: dffffc0000000000 R11: fffffbfff1efb90f R12: ffff88801ceddb80 R13: dffffc0000000000 R14: ffff88801cea5b80 R15: ffff8880b873ad58 context_switch kernel/sched/core.c:5267 [inline] __schedule+0x1850/0x4ec0 kernel/sched/core.c:6872 __schedule_loop kernel/sched/core.c:6954 [inline] schedule+0x165/0x360 kernel/sched/core.c:6969 smpboot_thread_fn+0x5bd/0xa60 kernel/smpboot.c:156 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 0f 84 3c 01 00 00 je 0x142 6: 48 85 db test %rbx,%rbx 9: 0f 85 63 01 00 00 jne 0x172 f: e9 2f 05 00 00 jmp 0x543 14: 4c 8b 75 d0 mov -0x30(%rbp),%r14 18: 4c 89 e7 mov %r12,%rdi 1b: e8 3f 6c c9 09 call 0x9c96c5f 20: e8 0a 3e 37 00 call 0x373e2f 25: fb sti 26: 4c 8b 65 c0 mov -0x40(%rbp),%r12 * 2a: 49 8d bc 24 60 16 00 lea 0x1660(%r12),%rdi <-- trapping instruction 31: 00 32: 48 89 f8 mov %rdi,%rax 35: 48 c1 e8 03 shr $0x3,%rax 39: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax 3e: 84 c0 test %al,%al