------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x10d/0x210, CPU#0: syz-executor.3/4048
Modules linked in:
CPU: 0 UID: 0 PID: 4048 Comm: syz-executor.3 Not tainted 6.18.0-rc5-next-20251113 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x10d/0x210
Code: 9b 0c 04 31 ff 89 de e8 31 8b 1f ff 84 db 75 9f e8 58 90 1f ff c6 05 5e 9b 0c 04 01 90 48 c7 c7 80 07 03 85 e8 54 bc e4 fe 90 <0f> 0b 90 90 e9 7c ff ff ff e8 35 90 1f ff 0f b6 1d 39 9b 0c 04 31
RSP: 0018:ffff88801926f9e0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc900047cd000
RDX: 0000000000040000 RSI: ffffffff813a403e RDI: 0000000000000001
RBP: ffff88800b00022c R08: 0000000000000001 R09: ffffed100324def3
R10: 0000000000000001 R11: 0000000000000001 R12: ffff88800b000200
R13: ffff88800b00022c R14: ffff888013f74410 R15: ffff888048ff5bb8
FS: 00007fd1534ca700(0000) GS:ffff8880e5394000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f911cb1e958 CR3: 000000001f085000 CR4: 0000000000350ef0
Call Trace:
nsproxy_free+0x4d3/0x5a0
create_new_namespaces+0x585/0x750
copy_namespaces+0x45c/0x580
copy_process+0x26e4/0x72a0
kernel_clone+0xea/0x7f0
__do_sys_clone3+0x1f5/0x280
do_syscall_64+0xbf/0x430
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd155f75b19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd1534ca188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007fd156089020 RCX: 00007fd155f75b19
RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880
RBP: 00007fd155fcff6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc549b85ef R14: 00007fd1534ca300 R15: 0000000000022000
irq event stamp: 8175
hardirqs last enabled at (8183): [] __up_console_sem+0x78/0x80
hardirqs last disabled at (8192): [] __up_console_sem+0x5d/0x80
softirqs last enabled at (8162): [] handle_softirqs+0x50c/0x770
softirqs last disabled at (8145): [] __irq_exit_rcu+0xc4/0x100
---[ end trace 0000000000000000 ]---
Oops: general protection fault, probably for non-canonical address 0xe0967c1e60000006: 0000 [#1] SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x04b400f300000030-0x04b400f300000037]
CPU: 0 UID: 0 PID: 4048 Comm: syz-executor.3 Tainted: G W 6.18.0-rc5-next-20251113 #1 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:nsproxy_free+0x1ab/0x5a0
Code: 0f 85 b4 03 00 00 4c 8b 65 38 4d 85 e4 74 41 e8 2b 48 30 00 49 8d 7c 24 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b8 03 00 00 49 8b 5c 24 30 bf 08 00 00 00 48 89
RSP: 0018:ffff88801926f9f8 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: ffffc900047cd000
RDX: 0096801e60000006 RSI: ffffffff8144ca85 RDI: 04b400f300000030
RBP: ffff88800b722820 R08: 0000000000000001 R09: ffffed100324def3
R10: 0000000000000001 R11: 0000000000000001 R12: 04b400f300000000
R13: ffff88800b00022c R14: ffff888013f74410 R15: ffff888048ff5bb8
FS: 00007fd1534ca700(0000) GS:ffff8880e5394000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f911cb1e958 CR3: 000000001f085000 CR4: 0000000000350ef0
Call Trace:
create_new_namespaces+0x585/0x750
copy_namespaces+0x45c/0x580
copy_process+0x26e4/0x72a0
kernel_clone+0xea/0x7f0
__do_sys_clone3+0x1f5/0x280
do_syscall_64+0xbf/0x430
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd155f75b19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd1534ca188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007fd156089020 RCX: 00007fd155f75b19
RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880
RBP: 00007fd155fcff6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc549b85ef R14: 00007fd1534ca300 R15: 0000000000022000
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nsproxy_free+0x1ab/0x5a0
Code: 0f 85 b4 03 00 00 4c 8b 65 38 4d 85 e4 74 41 e8 2b 48 30 00 49 8d 7c 24 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b8 03 00 00 49 8b 5c 24 30 bf 08 00 00 00 48 89
RSP: 0018:ffff88801926f9f8 EFLAGS: 00010216
RAX: dffffc0000000000 RBX: 00000000ffffffff RCX: ffffc900047cd000
RDX: 0096801e60000006 RSI: ffffffff8144ca85 RDI: 04b400f300000030
RBP: ffff88800b722820 R08: 0000000000000001 R09: ffffed100324def3
R10: 0000000000000001 R11: 0000000000000001 R12: 04b400f300000000
R13: ffff88800b00022c R14: ffff888013f74410 R15: ffff888048ff5bb8
FS: 00007fd1534ca700(0000) GS:ffff8880e5394000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f911cb1e958 CR3: 000000001f085000 CR4: 0000000000350ef0
loop6: detected capacity change from 0 to 248
FAT-fs (loop7): unable to read boot sector
ISO 9660 Extensions: Microsoft Joliet Level 3
loop6: detected capacity change from 0 to 248
ISO 9660 Extensions: Microsoft Joliet Level 3
----------------
Code disassembly (best guess):
0: 0f 85 b4 03 00 00 jne 0x3ba
6: 4c 8b 65 38 mov 0x38(%rbp),%r12
a: 4d 85 e4 test %r12,%r12
d: 74 41 je 0x50
f: e8 2b 48 30 00 callq 0x30483f
14: 49 8d 7c 24 30 lea 0x30(%r12),%rdi
19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
20: fc ff df
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 b8 03 00 00 jne 0x3ec
34: 49 8b 5c 24 30 mov 0x30(%r12),%rbx
39: bf 08 00 00 00 mov $0x8,%edi
3e: 48 rex.W
3f: 89 .byte 0x89