------------[ cut here ]------------ WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#0: syz.4.456/7367 WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#0: syz.4.456/7367 WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#0: syz.4.456/7367 Modules linked in: CPU: 0 UID: 0 PID: 7367 Comm: syz.4.456 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:ffffc90000007ba8 EFLAGS: 00010246 RAX: ffffffff818e8124 RBX: ffff888032c10aa0 RCX: ffff88802c43db80 RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 0000000000000004 R08: ffff88805797c193 R09: 1ffff1100af2f832 R10: dffffc0000000000 R11: ffffed100af2f833 R12: dffffc0000000000 R13: ffff888032c10a00 R14: ffff88805797c000 R15: ffff88805797c190 FS: 00007f70a16a86c0(0000) GS:ffff888125ecd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f33e2888f98 CR3: 0000000075590000 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 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1055 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1055 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 4b 39 d7 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003eff558 EFLAGS: 00000206 RAX: 3fb441f179f1cb00 RBX: 0000000000000206 RCX: 3fb441f179f1cb00 RDX: 0000000000000003 RSI: ffffffff8d96f159 RDI: ffffffff8bbf40e0 RBP: ffff88802c43e728 R08: ffff888032a41903 R09: 1ffff11006548320 R10: dffffc0000000000 R11: ffffed1006548321 R12: 0000000000000003 R13: 0000000000000003 R14: ffffffff8df3d860 R15: ffff88802c43db80 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] pte_unmap include/linux/pgtable.h:136 [inline] filemap_map_pages+0x18cf/0x1e20 mm/filemap.c:3930 do_fault_around mm/memory.c:5721 [inline] do_read_fault mm/memory.c:5754 [inline] do_fault mm/memory.c:5897 [inline] do_pte_missing+0x20db/0x3340 mm/memory.c:4409 handle_pte_fault mm/memory.c:6242 [inline] __handle_mm_fault mm/memory.c:6389 [inline] handle_mm_fault+0x1999/0x32a0 mm/memory.c:6558 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1650/0x29f0 mm/gup.c:1428 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860 __mm_populate+0x24c/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3524 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586 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: 0033:0x7f70a078f6c9 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:00007f70a16a8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f70a09e5fa0 RCX: 00007f70a078f6c9 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f70a0811f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f70a09e6038 R14: 00007f70a09e5fa0 R15: 00007ffd311dd4e8 ---------------- Code disassembly (best guess): 0: 51 push %rcx 1: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp) 8: 00 00 a: 9c pushf b: 8f 44 24 20 pop 0x20(%rsp) f: f7 44 24 20 00 02 00 testl $0x200,0x20(%rsp) 16: 00 17: 75 56 jne 0x6f 19: f7 c3 00 02 00 00 test $0x200,%ebx 1f: 74 01 je 0x22 21: fb sti 22: 65 48 8b 05 4b 39 d7 mov %gs:0x10d7394b(%rip),%rax # 0x10d73975 29: 10 * 2a: 48 3b 44 24 28 cmp 0x28(%rsp),%rax <-- trapping instruction 2f: 0f 85 8b 00 00 00 jne 0xc0 35: 48 83 c4 30 add $0x30,%rsp 39: 5b pop %rbx 3a: 41 5c pop %r12 3c: 41 5d pop %r13 3e: 41 5e pop %r14