------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#1: syz.1.1111/9827
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#1: syz.1.1111/9827
WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#1: syz.1.1111/9827
Modules linked in:
CPU: 1 UID: 0 PID: 9827 Comm: syz.1.1111 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 e8 d0 8d 00 e8 13 a7 32 00 4c 89 e7 be 03 00 00 00 e8 46 a1 0a 03 e9 b8 fe ff ff e8 fc a6 32 00 90 <0f> 0b 90 eb 9f e8 f1 a6 32 00 4c 89 ff be 03 00 00 00 e8 24 a1 0a
RSP: 0018:ffffc90000a08ba8 EFLAGS: 00010246
RAX: ffffffff818f2934 RBX: ffff88802f3e62a0 RCX: ffff888025cb5b80
RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffff88806ba84193 R09: 1ffff1100d750832
R10: dffffc0000000000 R11: ffffed100d750833 R12: dffffc0000000000
R13: ffff88802f3e6200 R14: ffff88806ba84000 R15: ffff88806ba84190
FS: 0000000000000000(0000) GS:ffff888125b79000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd70e033d58 CR3: 000000007a40c000 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:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 da 50 36 f6 48 89 df e8 32 e8 36 f6 e8 ad 44 61 f6 fb bf 01 00 00 00 22 d8 28 f6 65 8b 05 ab 1f 52 07 85 c0 74 07 5b e9 91 4d 00 00
RSP: 0018:ffffc90003b8e4f0 EFLAGS: 00000286
RAX: 81af459b6e2d3400 RBX: ffff8880679c6588 RCX: 81af459b6e2d3400
RDX: 0000000000000006 RSI: ffffffff8da864c6 RDI: 0000000000000001
RBP: ffffc90003b8e668 R08: ffffffff8fbf4577 R09: 1ffffffff1f7e8ae
R10: dffffc0000000000 R11: fffffbfff1f7e8af R12: ffffea00018da0c0
R13: dffffc0000000000 R14: 00000003fffffffc R15: 0000000000000001
spin_unlock_irq include/linux/spinlock.h:401 [inline]
__filemap_add_folio+0xda5/0x12f0 mm/filemap.c:930
filemap_add_folio+0x26d/0x540 mm/filemap.c:966
__filemap_get_folio_mpol+0x500/0xb00 mm/filemap.c:2016
__filemap_get_folio include/linux/pagemap.h:763 [inline]
simple_write_begin+0x64/0x500 fs/libfs.c:931
generic_perform_write+0x2c5/0x900 mm/filemap.c:4313
generic_file_write_iter+0x117/0x550 mm/filemap.c:4456
__kernel_write_iter+0x428/0x910 fs/read_write.c:619
dump_emit_page fs/coredump.c:1298 [inline]
dump_user_range+0x8a0/0xc90 fs/coredump.c:1372
elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111
coredump_write+0x116c/0x1900 fs/coredump.c:1049
do_coredump fs/coredump.c:1126 [inline]
vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200
get_signal+0x1108/0x1340 kernel/signal.c:3019
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 kernel/entry/common.c:75 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
irqentry_exit+0x171/0x640 kernel/entry/common.c:196
exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7ff19fe4f6b7
Code: 88 15 42 60 ec 00 88 05 3f 60 ec 00 c3 50 48 8d 35 e9 28 1c 00 48 8d 3d ef 28 1c 00 31 c0 e8 20 f7 ff ff 53 89 fb 48 83 ec 10 <64> 8b 04 25 94 ff ff ff 85 c0 74 2a 89 fe 31 c0 bf 3c 00 00 00 e8
RSP: 002b:00007ff1a0d7c120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007ff19ff8f6c9
RDX: 00007ff1a0d7c140 RSI: 00007ff1a0d7c270 RDI: 000000000000000b
RBP: 00007ff1a0011f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ff1a01e6218 R14: 00007ff1a01e6180 R15: 00007fff7aa7cd18
----------------
Code disassembly (best guess):
0: 90 nop
1: f3 0f 1e fa endbr64
5: 53 push %rbx
6: 48 89 fb mov %rdi,%rbx
9: 48 83 c7 18 add $0x18,%rdi
d: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
12: e8 da 50 36 f6 call 0xf63650f1
17: 48 89 df mov %rbx,%rdi
1a: e8 32 e8 36 f6 call 0xf636e851
1f: e8 ad 44 61 f6 call 0xf66144d1
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 22 d8 28 f6 call 0xf628d851 <-- trapping instruction
2f: 65 8b 05 ab 1f 52 07 mov %gs:0x7521fab(%rip),%eax # 0x7521fe1
36: 85 c0 test %eax,%eax
38: 74 07 je 0x41
3a: 5b pop %rbx
3b: e9 91 4d 00 00 jmp 0x4dd1