audit: type=1400 audit(1763323026.289:10): avc: denied { write } for pid=4118 comm="syz-executor.4" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=perf_event permissive=1
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x10d/0x210, CPU#0: syz-executor.4/4127
Modules linked in:
CPU: 0 UID: 0 PID: 4127 Comm: syz-executor.4 Not tainted 6.18.0-rc5-next-20251114 #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: 15 0c 04 31 ff 89 de e8 51 22 1f ff 84 db 75 9f e8 78 27 1f ff c6 05 0e 15 0c 04 01 90 48 c7 c7 a0 07 03 85 e8 54 43 e4 fe 90 <0f> 0b 90 90 e9 7c ff ff ff e8 55 27 1f ff 0f b6 1d e9 14 0c 04 31
RSP: 0018:ffff88804a03f9e0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc900093f3000
RDX: 0000000000040000 RSI: ffffffff813a514e RDI: 0000000000000001
RBP: ffffea00003ed36c R08: 0000000000000001 R09: ffffed100d9c4849
R10: 0000000000000001 R11: 0000000000000001 R12: ffffea00003ed340
R13: ffffea00003ed36c R14: ffffffff85cfdf20 R15: ffff888015fa2438
FS: 00007f6551863700(0000) GS:ffff8880e538f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c010ae4000 CR3: 00000000201cf000 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: 0033:0x7f655430eb19
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:00007f6551863188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f6554422020 RCX: 00007f655430eb19
RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880
RBP: 00007f6554368f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc45fd552f R14: 00007f6551863300 R15: 0000000000022000
irq event stamp: 7761
hardirqs last enabled at (7771): [] __up_console_sem+0x78/0x80
hardirqs last disabled at (7780): [] __up_console_sem+0x5d/0x80
softirqs last enabled at (7710): [] handle_softirqs+0x50c/0x770
softirqs last disabled at (7705): [] __irq_exit_rcu+0xc4/0x100
---[ end trace 0000000000000000 ]---
Oops: general protection fault, probably for non-canonical address 0xdffffc000000002e: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000170-0x0000000000000177]
CPU: 0 UID: 0 PID: 4127 Comm: syz-executor.4 Tainted: G W 6.18.0-rc5-next-20251114 #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+0x28a/0x5a0
Code: 02 00 00 4c 8b 65 28 4d 85 e4 74 43 e8 7f 56 30 00 49 8d bc 24 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f7 02 00 00 49 8b 9c 24 78 01 00 00 bf 08 00 00
RSP: 0018:ffff88804a03f9f8 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900093f3000
RDX: 000000000000002e RSI: ffffffff8144dd61 RDI: 0000000000000174
RBP: ffff88800c272b60 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8664ed57 R11: 0000000000000001 R12: fffffffffffffffc
R13: ffff88801651be1c R14: ffffffff85cfdf20 R15: ffff888015fa2438
FS: 00007f6551863700(0000) GS:ffff8880e538f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c010ae4000 CR3: 00000000201cf000 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: 0033:0x7f655430eb19
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:00007f6551863188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f6554422020 RCX: 00007f655430eb19
RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880
RBP: 00007f6554368f6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc45fd552f R14: 00007f6551863300 R15: 0000000000022000
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nsproxy_free+0x28a/0x5a0
Code: 02 00 00 4c 8b 65 28 4d 85 e4 74 43 e8 7f 56 30 00 49 8d bc 24 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 f7 02 00 00 49 8b 9c 24 78 01 00 00 bf 08 00 00
RSP: 0018:ffff88804a03f9f8 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffc900093f3000
RDX: 000000000000002e RSI: ffffffff8144dd61 RDI: 0000000000000174
RBP: ffff88800c272b60 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8664ed57 R11: 0000000000000001 R12: fffffffffffffffc
R13: ffff88801651be1c R14: ffffffff85cfdf20 R15: ffff888015fa2438
FS: 00007f6551863700(0000) GS:ffff8880e538f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c010ae4000 CR3: 00000000201cf000 CR4: 0000000000350ef0
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.6'.
loop4: detected capacity change from 0 to 264192
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'.
----------------
Code disassembly (best guess):
0: 02 00 add (%rax),%al
2: 00 4c 8b 65 add %cl,0x65(%rbx,%rcx,4)
6: 28 4d 85 sub %cl,-0x7b(%rbp)
9: e4 74 in $0x74,%al
b: 43 e8 7f 56 30 00 rex.XB callq 0x305690
11: 49 8d bc 24 78 01 00 lea 0x178(%r12),%rdi
18: 00
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 f7 02 00 00 jne 0x32b
34: 49 8b 9c 24 78 01 00 mov 0x178(%r12),%rbx
3b: 00
3c: bf .byte 0xbf
3d: 08 00 or %al,(%rax)