R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 00007fffa0e893df R14: 00007fa065373300 R15: 0000000000022000 ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x10d/0x210, CPU#1: syz-executor.3/6300 Modules linked in: CPU: 1 UID: 0 PID: 6300 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:ffff8880560ff9e0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000b457000 RDX: 0000000000040000 RSI: ffffffff813a403e RDI: 0000000000000001 RBP: ffff88801c6e227c R08: 0000000000000001 R09: ffffed100ac1fef3 R10: 0000000000000001 R11: 0000000000000001 R12: ffff88801c6e2250 R13: ffff88801c6e227c R14: ffff8880558a38e0 R15: ffff888050aedbb8 FS: 00007f89225e7700(0000) GS:ffff8880e5494000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe327c1d5d0 CR3: 0000000057412000 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: 0033:0x7f8925071b19 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:00007f89225e7188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f8925184f60 RCX: 00007f8925071b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880 RBP: 00007f89250cbf6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffedb54b8ef R14: 00007f89225e7300 R15: 0000000000022000 irq event stamp: 10927 hardirqs last enabled at (11931): [] __up_console_sem+0x78/0x80 hardirqs last disabled at (13006): [] __up_console_sem+0x5d/0x80 softirqs last enabled at (13478): [] handle_softirqs+0x50c/0x770 softirqs last disabled at (13489): [] __irq_exit_rcu+0xc4/0x100 ---[ end trace 0000000000000000 ]--- Oops: general protection fault, probably for non-canonical address 0xe0b87c208000030d: 0000 [#1] SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0x05c4010400001868-0x05c401040000186f] CPU: 1 UID: 0 PID: 6300 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:ffff8880560ff9f8 EFLAGS: 00010213 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000b457000 RDX: 00b880208000030d RSI: ffffffff8144ca85 RDI: 05c401040000186d RBP: ffff8880565bd1a0 R08: 0000000000000001 R09: ffffed100ac1fef3 R10: 0000000000000001 R11: 0000000000000001 R12: 05c401040000183d R13: ffff88801c6e227c R14: ffff8880558a38e0 R15: ffff888050aedbb8 FS: 00007f89225e7700(0000) GS:ffff8880e5494000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe327c1d5d0 CR3: 0000000057412000 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: 0033:0x7f8925071b19 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:00007f89225e7188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f8925184f60 RCX: 00007f8925071b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880 RBP: 00007f89250cbf6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffedb54b8ef R14: 00007f89225e7300 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:ffff8880560ff9f8 EFLAGS: 00010213 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000b457000 RDX: 00b880208000030d RSI: ffffffff8144ca85 RDI: 05c401040000186d RBP: ffff8880565bd1a0 R08: 0000000000000001 R09: ffffed100ac1fef3 R10: 0000000000000001 R11: 0000000000000001 R12: 05c401040000183d R13: ffff88801c6e227c R14: ffff8880558a38e0 R15: ffff888050aedbb8 FS: 00007f89225e7700(0000) GS:ffff8880e5494000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe327c1d5d0 CR3: 0000000057412000 CR4: 0000000000350ef0 ext3: Unknown parameter 'noacl' FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 UID: 0 PID: 6366 Comm: syz-executor.1 Tainted: G D W 6.18.0-rc5-next-20251113 #1 PREEMPT(voluntary) Tainted: [D]=DIE, [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: dump_stack_lvl+0xfa/0x120 should_fail_ex+0x4d7/0x5e0 should_failslab+0xc2/0x120 __kmalloc_noprof+0xcd/0x680 __register_sysctl_table+0xd4f/0x16a0 setup_userns_sysctls+0xcb/0x190 create_user_ns+0x8f7/0xd40 copy_creds+0x4a7/0xa30 copy_process+0xf59/0x72a0 kernel_clone+0xea/0x7f0 __do_sys_clone3+0x1f5/0x280 do_syscall_64+0xbf/0x430 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f37e2d6bb19 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:00007f37e02e1188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f37e2e7ef60 RCX: 00007f37e2d6bb19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880 RBP: 00007f37e02e11d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 00007fffc913854f R14: 00007f37e02e1300 R15: 0000000000022000 sysctl could not get directory: /user -12 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 0 UID: 0 PID: 6373 Comm: syz-executor.5 Tainted: G D W 6.18.0-rc5-next-20251113 #1 PREEMPT(voluntary) Tainted: [D]=DIE, [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: dump_stack_lvl+0xfa/0x120 should_fail_ex+0x4d7/0x5e0 should_failslab+0xc2/0x120 __kmalloc_cache_noprof+0x81/0x6b0 copy_ipcs+0x10c/0x680 create_new_namespaces+0x202/0x750 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: 0033:0x7f98d5ac8b19 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:00007f98d303e188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f98d5bdbf60 RCX: 00007f98d5ac8b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880 RBP: 00007f98d303e1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 00007ffd3c720e0f R14: 00007f98d303e300 R15: 0000000000022000 ext3: Unknown parameter 'noacl' Oops: general protection fault, probably for non-canonical address 0xdffffc000000012c: 0000 [#2] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000960-0x0000000000000967] CPU: 0 UID: 0 PID: 6373 Comm: syz-executor.5 Tainted: G D W 6.18.0-rc5-next-20251113 #1 PREEMPT(voluntary) Tainted: [D]=DIE, [W]=WARN Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:put_ipc_ns+0x30/0xa0 Code: 89 fd 53 e8 62 95 4e ff 48 85 ed 74 3d e8 58 95 4e ff 48 8d bd 70 09 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 5c 48 8b 9d 70 09 00 00 bf 08 00 00 00 48 89 de e8 RSP: 0018:ffff88805368f9e0 EFLAGS: 00010213 ext3: Unknown parameter 'noacl' RAX: dffffc0000000000 RBX: 000000000000001f RCX: ffffc90005628000 RDX: 000000000000012c RSI: ffffffff82267d58 RDI: 0000000000000964 RBP: fffffffffffffff4 R08: 0000000000000001 R09: ffffed1002f14091 R10: 000000000000001f R11: 0000000000000001 R12: ffff8880178a02d8 R13: ffff8880178a048c R14: ffff8880523f2cb0 R15: ffff88804e0c8878 FS: 00007f98d303e700(0000) GS:ffff8880e5394000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f98d303df78 CR3: 000000001c798000 CR4: 0000000000350ef0 Call Trace: nsproxy_free+0xd2/0x5a0 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: 0033:0x7f98d5ac8b19 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:00007f98d303e188 EFLAGS: 00000246 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00007f98d5bdbf60 RCX: 00007f98d5ac8b19 RDX: 0000000000000000 RSI: 0000000000000058 RDI: 0000000020005880 RBP: 00007f98d303e1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 00007ffd3c720e0f R14: 00007f98d303e300 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:ffff8880560ff9f8 EFLAGS: 00010213 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000b457000 RDX: 00b880208000030d RSI: ffffffff8144ca85 RDI: 05c401040000186d RBP: ffff8880565bd1a0 R08: 0000000000000001 R09: ffffed100ac1fef3 R10: 0000000000000001 R11: 0000000000000001 R12: 05c401040000183d R13: ffff88801c6e227c R14: ffff8880558a38e0 R15: ffff888050aedbb8 FS: 00007f98d303e700(0000) GS:ffff8880e5394000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f98d303df78 CR3: 000000001c798000 CR4: 0000000000350ef0 ---------------- 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