------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 4170 at lib/refcount.c:25 refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 4170 Comm: syz-executor Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:refcount_warn_saturate+0xff/0x1a0 lib/refcount.c:25 Code: 09 01 48 c7 c7 40 6b 59 8a e8 dd 27 bb 05 0f 0b eb e0 e8 04 42 9c fd c6 05 ae 8f 79 09 01 48 c7 c7 80 6a 59 8a e8 c1 27 bb 05 <0f> 0b eb c4 e8 e8 41 9c fd c6 05 93 8f 79 09 01 48 c7 c7 e0 6a 59 RSP: 0018:ffffc90000007848 EFLAGS: 00010246 RAX: e7424ca9617a5e00 RBX: 0000000000000002 RCX: ffff88807ad7bb80 RDX: 0000000000000100 RSI: 0000000000000101 RDI: 0000000000000000 RBP: ffffc900000079b0 R08: dffffc0000000000 R09: fffff52000000e6d R10: fffff52000000e6d R11: 1ffff92000000e6c R12: ffff88801adc3500 R13: dffffc0000000000 R14: 0000000000000002 R15: 0000000000000000 FS: 0000555564966500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7ec7705db3 CR3: 0000000063d44000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] get_net include/net/net_namespace.h:252 [inline] tipc_aead_encrypt net/tipc/crypto.c:832 [inline] tipc_crypto_xmit+0x1949/0x2560 net/tipc/crypto.c:1772 tipc_bearer_xmit_skb+0x228/0x3c0 net/tipc/bearer.c:574 tipc_disc_timeout+0x568/0x6b0 net/tipc/discover.c:338 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] RIP: 0010:rcu_is_watching+0x56/0xa0 kernel/rcu/tree.c:1123 Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 50 9d 59 00 48 c7 c3 c8 b2 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 2b 8b 03 65 ff 0d c5 d2 9e 7e 74 08 24 01 5b 41 5e 41 5f RSP: 0018:ffffc90002e7f960 EFLAGS: 00000a06 RAX: 0000000000000000 RBX: ffff8880b903b2c8 RCX: e7424ca9617a5e00 RDX: ffffc90002e7ff00 RSI: ffffffff8a59a720 RDI: ffffffff8a59a6e0 RBP: ffffc90002e7fa50 R08: 0000000000000004 R09: 0000000000000008 R10: fffff520005cff45 R11: 1ffff920005cff43 R12: ffff88807ad7bb80 R13: ffff888050eea200 R14: ffffffff8bbaf810 R15: dffffc0000000000 kernel_text_address kernel/extable.c:139 [inline] __kernel_text_address+0x71/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kmem_cache_free+0x8f/0x210 mm/slub.c:3515 putname fs/namei.c:271 [inline] do_mkdirat+0x514/0x5a0 fs/namei.c:4099 __do_sys_mkdirat fs/namei.c:4105 [inline] __se_sys_mkdirat fs/namei.c:4103 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ffa5f5c5197 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffe256e548 EFLAGS: 00000206 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007fffe256e5a0 RCX: 00007ffa5f5c5197 RDX: 00000000000001ff RSI: 00007fffe256e5a0 RDI: 00000000ffffff9c RBP: 00007fffe256e58c R08: 0000000000000005 R09: 00007fffe256e2e5 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000bf R13: 00000000000927c0 R14: 0000000000042360 R15: 00007fffe256e5e0 ---------------- Code disassembly (best guess): 0: f0 48 c1 e8 03 lock shr $0x3,%rax 5: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) a: 74 08 je 0x14 c: 4c 89 f7 mov %r14,%rdi f: e8 50 9d 59 00 call 0x599d64 14: 48 c7 c3 c8 b2 03 00 mov $0x3b2c8,%rbx 1b: 49 03 1e add (%r14),%rbx 1e: 48 89 d8 mov %rbx,%rax 21: 48 c1 e8 03 shr $0x3,%rax 25: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 75 2b jne 0x59 2e: 8b 03 mov (%rbx),%eax 30: 65 ff 0d c5 d2 9e 7e decl %gs:0x7e9ed2c5(%rip) # 0x7e9ed2fc 37: 74 08 je 0x41 39: 24 01 and $0x1,%al 3b: 5b pop %rbx 3c: 41 5e pop %r14 3e: 41 5f pop %r15