vcan0: j1939_tp_rxtimer: 0xffff88805727e800: rx timeout, send abort vcan0: j1939_tp_rxtimer: 0xffff88805727f000: abort rx timeout. Force session deactivation vcan0: j1939_tp_rxtimer: 0xffff88805727e800: abort rx timeout. Force session deactivation ------------[ cut here ]------------ WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#0: syz.0.149/6400 WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#0: syz.0.149/6400 WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#0: syz.0.149/6400 Modules linked in: CPU: 0 UID: 0 PID: 6400 Comm: syz.0.149 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:__ns_ref_put include/linux/ns_common.h:255 [inline] RIP: 0010:put_user_ns include/linux/user_namespace.h:189 [inline] RIP: 0010:put_cred_rcu+0x2c5/0x340 kernel/cred.c:61 Code: 5c 41 5d 41 5e 41 5f 5d e9 48 e1 8d 00 e8 03 8c 32 00 4c 89 e7 be 03 00 00 00 e8 d6 27 00 03 e9 b8 fe ff ff e8 ec 8b 32 00 90 <0f> 0b 90 eb 9f e8 e1 8b 32 00 4c 89 ff be 03 00 00 00 e8 b4 27 00 RSP: 0018:ffffc90000007ba8 EFLAGS: 00010246 RAX: ffffffff818e8124 RBX: ffff8880254e5fa0 RCX: ffff88802a725b80 RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000 RBP: 0000000000000004 R08: ffff888056cac193 R09: 1ffff1100ad95832 R10: dffffc0000000000 R11: ffffed100ad95833 R12: dffffc0000000000 R13: ffff8880254e5f00 R14: ffff888056cac000 R15: ffff888056cac190 FS: 00007fd9457816c0(0000) GS:ffff888125ecd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30323ffc CR3: 000000007ae5e000 CR4: 00000000003526f0 Call Trace: rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:626 __do_softirq kernel/softirq.c:660 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1055 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1055 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:finish_task_switch+0x26b/0x960 kernel/sched/core.c:5118 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 2f 05 00 00 4c 8b 75 d0 4c 89 e7 e8 3f 6c c9 09 e8 0a 3e 37 00 fb 4c 8b 65 c0 <49> 8d bc 24 60 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc9001ab67738 EFLAGS: 00000282 RAX: db17671bd3704900 RBX: 0000000000000000 RCX: db17671bd3704900 RDX: 0000000000000000 RSI: ffffffff8d787b5c RDI: ffffffff8bbf40e0 RBP: ffffc9001ab67790 R08: ffffffff8f7dc877 R09: 1ffffffff1efb90e R10: dffffc0000000000 R11: fffffbfff1efb90f R12: ffff88802a725b80 R13: dffffc0000000000 R14: ffff8880262e5b80 R15: ffff8880b863ad58 context_switch kernel/sched/core.c:5267 [inline] __schedule+0x1850/0x4ec0 kernel/sched/core.c:6872 __schedule_loop kernel/sched/core.c:6954 [inline] schedule+0x165/0x360 kernel/sched/core.c:6969 futex_do_wait kernel/futex/waitwake.c:358 [inline] __futex_wait+0x1c3/0x3d0 kernel/futex/waitwake.c:687 futex_wait+0x104/0x360 kernel/futex/waitwake.c:715 do_futex+0x333/0x420 kernel/futex/syscalls.c:130 __do_sys_futex kernel/futex/syscalls.c:207 [inline] __se_sys_futex+0x36f/0x400 kernel/futex/syscalls.c:188 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd94498f6c9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd9457810e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fd944be5fa8 RCX: 00007fd94498f6c9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd944be5fa8 RBP: 00007fd944be5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd944be6038 R14: 00007ffcbf0d5b40 R15: 00007ffcbf0d5c28 ---------------- Code disassembly (best guess): 0: 0f 84 3c 01 00 00 je 0x142 6: 48 85 db test %rbx,%rbx 9: 0f 85 63 01 00 00 jne 0x172 f: e9 2f 05 00 00 jmp 0x543 14: 4c 8b 75 d0 mov -0x30(%rbp),%r14 18: 4c 89 e7 mov %r12,%rdi 1b: e8 3f 6c c9 09 call 0x9c96c5f 20: e8 0a 3e 37 00 call 0x373e2f 25: fb sti 26: 4c 8b 65 c0 mov -0x40(%rbp),%r12 * 2a: 49 8d bc 24 60 16 00 lea 0x1660(%r12),%rdi <-- trapping instruction 31: 00 32: 48 89 f8 mov %rdi,%rax 35: 48 c1 e8 03 shr $0x3,%rax 39: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax 3e: 84 c0 test %al,%al