------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 7782 at lib/refcount.c:25 refcount_warn_saturate+0x1ca/0x210 lib/refcount.c:25 Modules linked in: CPU: 1 UID: 0 PID: 7782 Comm: syz.2.550 Not tainted 6.15.0-syzkaller-11796-g5abc7438f1e9 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:refcount_warn_saturate+0x1ca/0x210 lib/refcount.c:25 Code: ff 89 de e8 f8 5c e4 fc 84 db 0f 85 e6 fe ff ff e8 0b 62 e4 fc c6 05 ce 94 98 0b 01 90 48 c7 c7 40 e1 f4 8b e8 17 2e a3 fc 90 <0f> 0b 90 90 e9 c3 fe ff ff e8 e8 61 e4 fc c6 05 a9 94 98 0b 01 90 RSP: 0000:ffffc90000a086e0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817ad368 RDX: ffff88803146bc00 RSI: ffffffff817ad375 RDI: 0000000000000001 RBP: ffff888034b5c26c R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888034b5c26c R13: ffff888034b5c100 R14: ffff888030318f00 R15: ffff8880343c7e00 FS: 000055556c549500(0000) GS:ffff888124a6c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c259197 CR3: 000000005df5a000 CR4: 0000000000350ef0 Call Trace: __refcount_add include/linux/refcount.h:289 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] get_net include/net/net_namespace.h:268 [inline] tipc_aead_encrypt net/tipc/crypto.c:821 [inline] tipc_crypto_xmit+0x20c1/0x2550 net/tipc/crypto.c:1761 tipc_crypto_clone_msg net/tipc/crypto.c:1656 [inline] tipc_crypto_xmit+0x1f09/0x2550 net/tipc/crypto.c:1717 tipc_bearer_xmit_skb+0x15f/0x430 net/tipc/bearer.c:572 tipc_disc_timeout+0x5b2/0x850 net/tipc/discover.c:338 call_timer_fn+0x19a/0x620 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1798 [inline] __run_timers+0x6ef/0x960 kernel/time/timer.c:2372 __run_timer_base kernel/time/timer.c:2384 [inline] __run_timer_base kernel/time/timer.c:2376 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2393 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: e6 3a 55 00 48 89 df 5b e9 9d c0 5a 00 be 03 00 00 00 5b e9 52 9c 1b 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 34 24 65 48 8b 15 58 3a ef 11 65 8b 05 69 3a ef RSP: 0000:ffffc90003097990 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffea0001a467c0 RCX: ffffffff822d794d RDX: ffff88803146bc00 RSI: ffffffff822d795b RDI: 0000000000000007 RBP: ffffffff8dd10440 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea0001a467c0 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 folio_test_slab include/linux/page-flags.h:1074 [inline] PageSlab include/linux/page-flags.h:1085 [inline] page_table_check_set+0xc8/0x750 mm/page_table_check.c:109 __page_table_check_ptes_set+0x318/0x420 mm/page_table_check.c:209 page_table_check_ptes_set include/linux/page_table_check.h:76 [inline] set_ptes include/linux/pgtable.h:292 [inline] set_pte_range+0x4e8/0x740 mm/memory.c:5350 filemap_map_order0_folio mm/filemap.c:3692 [inline] filemap_map_pages+0x56c/0x1680 mm/filemap.c:3746 do_fault_around mm/memory.c:5568 [inline] do_read_fault mm/memory.c:5601 [inline] do_fault mm/memory.c:5744 [inline] do_pte_missing mm/memory.c:4251 [inline] handle_pte_fault mm/memory.c:6089 [inline] __handle_mm_fault+0x3b3b/0x5490 mm/memory.c:6232 handle_mm_fault+0x589/0xd10 mm/memory.c:6401 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f648066ecad Code: ff 48 83 e8 01 48 89 ee bf 01 00 00 00 48 c1 e0 0e 48 c1 ee 06 48 01 c8 48 89 e9 81 e6 ff 3f 00 00 48 c1 e9 03 83 e1 07 d3 e7 <40> 84 bc 06 20 20 00 00 0f 85 11 fd ff ff e9 c0 fd ff ff e8 7b 2b RSP: 002b:00007fffef641300 EFLAGS: 00010212 RAX: 000000110c254000 RBX: 00007f64814e5720 RCX: 0000000000000001 RDX: 0000000000001dc8 RSI: 0000000000003177 RDI: 0000000000000002 RBP: ffffffff812c5dc8 R08: 00007f64809b6038 R09: 00007f64809a2000 R10: 00007f647fdff008 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff812c54b3 R15: 0000000000000004 ---------------- Code disassembly (best guess): 0: e6 3a out %al,$0x3a 2: 55 push %rbp 3: 00 48 89 add %cl,-0x77(%rax) 6: df 5b e9 fistps -0x17(%rbx) 9: 9d popf a: c0 5a 00 be rcrb $0xbe,0x0(%rdx) e: 03 00 add (%rax),%eax 10: 00 00 add %al,(%rax) 12: 5b pop %rbx 13: e9 52 9c 1b 03 jmp 0x31b9c6a 18: 66 90 xchg %ax,%ax 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 90 nop 26: 90 nop 27: 90 nop 28: 90 nop 29: 90 nop * 2a: f3 0f 1e fa endbr64 <-- trapping instruction 2e: 48 8b 34 24 mov (%rsp),%rsi 32: 65 48 8b 15 58 3a ef mov %gs:0x11ef3a58(%rip),%rdx # 0x11ef3a92 39: 11 3a: 65 gs 3b: 8b .byte 0x8b 3c: 05 .byte 0x5 3d: 69 .byte 0x69 3e: 3a ef cmp %bh,%ch