------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#0: syz.2.783/8958
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#0: syz.2.783/8958
WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#0: syz.2.783/8958
Modules linked in:
CPU: 0 UID: 0 PID: 8958 Comm: syz.2.783 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 78 8c 8d 00 e8 03 8c 32 00 4c 89 e7 be 03 00 00 00 e8 b6 d6 08 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 94 d6 08
RSP: 0018:ffffc90000007ba8 EFLAGS: 00010246
RAX: ffffffff818ed124 RBX: ffff888027c3b4a0 RCX: ffff88802c929e80
RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffff888078db85bb R09: 1ffff1100f1b70b7
R10: dffffc0000000000 R11: ffffed100f1b70b8 R12: dffffc0000000000
R13: ffff888027c3b400 R14: ffff888078db8428 R15: ffff888078db85b8
FS: 0000000000000000(0000) GS:ffff888125a83000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0d79e7dac CR3: 000000006a8f0000 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:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x4e/0xb0 kernel/rcu/tree.c:751
Code: ff df 4c 8d 34 dd d0 ad ca 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 8c 3f 80 00 48 c7 c3 98 01 bb 92 49 03 1e <48> 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 69
RSP: 0018:ffffc9000e0375f0 EFLAGS: 00000283
RAX: 1ffffffff1b955ba RBX: ffff8880b8633198 RCX: ead6315380948300
RDX: 0000000000000000 RSI: ffffffff8be11140 RDI: ffffffff8be11100
RBP: ffffffff8263d2cc R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100b6b5e79 R12: 0000000000000002
R13: ffffffff8e33d860 R14: ffffffff8dcaadd0 R15: dffffc0000000000
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5831
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
kernfs_root+0x38/0x230 fs/kernfs/kernfs-internal.h:75
kernfs_drain+0x8a/0x5e0 fs/kernfs/dir.c:493
__kernfs_remove+0x33b/0x5a0 fs/kernfs/dir.c:1508
kernfs_remove+0x38/0x60 fs/kernfs/dir.c:1550
__kobject_del+0xe1/0x330 lib/kobject.c:604
kobject_cleanup lib/kobject.c:680 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x243/0x570 lib/kobject.c:737
bus_remove_driver+0x245/0x320 drivers/base/bus.c:787
usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1751
raw_release+0xd7/0x260 drivers/usb/gadget/legacy/raw_gadget.c:462
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6bd/0x2300 kernel/exit.c:970
do_group_exit+0x21c/0x2d0 kernel/exit.c:1111
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0da7b8f6c9
Code: Unable to access opcode bytes at 0x7f0da7b8f69f.
RSP: 002b:00007f0da8971038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 00007f0da7de5fa0 RCX: 00007f0da7b8f6c9
RDX: 00000000200008c0 RSI: 0000200000000740 RDI: 0000000000000003
RBP: 00007f0da7c11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0da7de6038 R14: 00007f0da7de5fa0 R15: 00007fff456b8df8
----------------
Code disassembly (best guess), 1 bytes skipped:
0: df 4c 8d 34 fisttps 0x34(%rbp,%rcx,4)
4: dd d0 fst %st(0)
6: ad lods %ds:(%rsi),%eax
7: ca 8d 4c lret $0x4c8d
a: 89 f0 mov %esi,%eax
c: 48 c1 e8 03 shr $0x3,%rax
10: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1)
15: 74 08 je 0x1f
17: 4c 89 f7 mov %r14,%rdi
1a: e8 8c 3f 80 00 call 0x803fab
1f: 48 c7 c3 98 01 bb 92 mov $0xffffffff92bb0198,%rbx
26: 49 03 1e add (%r14),%rbx
* 29: 48 89 d8 mov %rbx,%rax <-- trapping instruction
2c: 48 c1 e8 03 shr $0x3,%rax
30: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
35: 84 c0 test %al,%al
37: 75 34 jne 0x6d
39: 8b 03 mov (%rbx),%eax
3b: 65 gs
3c: ff .byte 0xff
3d: 0d .byte 0xd
3e: 69 .byte 0x69