watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.1.3193:18829] Modules linked in: irq event stamp: 13257531 hardirqs last enabled at (13257530): [] irqentry_exit+0x59e/0x620 kernel/entry/common.c:242 hardirqs last disabled at (13257531): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (5050): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (5050): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (5050): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 softirqs last disabled at (5053): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (5053): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (5053): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 CPU: 0 UID: 0 PID: 18829 Comm: syz.1.3193 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x27/0x70 kernel/kcov.c:217 Code: 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 28 1b 57 11 65 8b 15 49 1b 57 11 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 <83> b9 a4 16 00 00 00 74 2c 8b 91 80 16 00 00 83 fa 02 75 21 48 8b RSP: 0018:ffffc90000007ad8 EFLAGS: 00000246 RAX: ffffffff897673c7 RBX: dffffc0000000000 RCX: ffff88802f565b80 RDX: 0000000000000100 RSI: 0000000000000008 RDI: ffff8880497f3140 RBP: 0000000000000008 R08: 0000000000000000 R09: 1ffff110058a9aa4 R10: dffffc0000000000 R11: ffffed10058a9aa5 R12: 000000000000000f R13: 0000000000000001 R14: ffff8880497f3140 R15: 0000000000000008 FS: 00007f523b01d6c0(0000) GS:ffff888125453000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c36f148 CR3: 00000000419b8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: skb_put+0x27/0x210 net/core/skbuff.c:2649 __ndisc_fill_addr_option+0x3e/0x140 net/ipv6/ndisc.c:150 ndisc_fill_addr_option net/ipv6/ndisc.c:171 [inline] ndisc_send_rs+0x41f/0x630 net/ipv6/ndisc.c:718 addrconf_rs_timer+0x395/0x6d0 net/ipv6/addrconf.c:4042 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:417 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 2b 2a 80 f5 cc RSP: 0018:ffffc90004faf650 EFLAGS: 00000297 RAX: ffffffff81c9f276 RBX: 1ffff11005eacb70 RCX: 0000000000000002 RDX: ffff88802f565b80 RSI: 0000000080000001 RDI: 0000000000000000 RBP: 0000000000000020 R08: ffffc90004faf8cf R09: 0000000000000000 R10: ffffc90004faf8c0 R11: fffff520009f5f1a R12: 0000000080000001 R13: 0000000000000000 R14: 0000000080000001 R15: ffff88802f565b80 tracing_gen_ctx_irq_test+0xc6/0x160 kernel/trace/trace.c:2199 tracing_gen_ctx_flags include/linux/trace_events.h:201 [inline] tracing_gen_ctx include/linux/trace_events.h:208 [inline] perf_trace_buf_update+0x3f/0x190 kernel/trace/trace_event_perf.c:429 perf_tp_event+0x1f3/0x2a90 kernel/events/core.c:11401 perf_trace_run_bpf_submit+0xee/0x170 kernel/events/core.c:11334 do_perf_trace_lock_acquire include/trace/events/lock.h:24 [inline] perf_trace_lock_acquire+0x345/0x440 include/trace/events/lock.h:24 __do_trace_lock_acquire include/trace/events/lock.h:24 [inline] trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2a4/0x2e0 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] futex_hash+0x5d/0x2d0 kernel/futex/core.c:308 class_hb_constructor kernel/futex/futex.h:240 [inline] futex_wake+0x18f/0x580 kernel/futex/waitwake.c:172 do_futex+0x395/0x420 kernel/futex/syscalls.c:135 __do_sys_futex kernel/futex/syscalls.c:207 [inline] __se_sys_futex+0x3a8/0x450 kernel/futex/syscalls.c:188 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f523a19c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f523b01d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f523a415fa8 RCX: 00007f523a19c819 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f523a415fac RBP: 00007f523a415fa0 R08: 3fffffffffffffff R09: 0000000000000000 R10: 0000000000000054 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f523a416038 R14: 00007ffedd3e4210 R15: 00007ffedd3e42f8 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 eb 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f e7 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 e7 RSP: 0018:ffffc90000126220 EFLAGS: 00000293 RAX: ffffffff81b9cd6d RBX: 1ffff110170c8525 RCX: ffff88801da95b80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000126350 R08: ffff888033cbc8c7 R09: 1ffff11006797918 R10: dffffc0000000000 R11: ffffffff81787350 R12: ffff8880b8642928 R13: dffffc0000000000 R14: ffff8880b873c000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125553000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7890615d58 CR3: 000000005ec4e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472 flush_tlb_page arch/x86/include/asm/tlbflush.h:323 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103 page_vma_mkclean_one+0x438/0x780 mm/rmap.c:1132 page_mkclean_one+0x1d8/0x2b0 mm/rmap.c:1180 __rmap_walk_file+0x467/0x620 mm/rmap.c:3056 rmap_walk mm/rmap.c:3100 [inline] folio_mkclean+0x2bb/0x3d0 mm/rmap.c:1212 folio_clear_dirty_for_io+0x1a5/0x710 mm/page-writeback.c:2888 mpage_submit_folio+0x86/0x2b0 fs/ext4/inode.c:2071 mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2201 mpage_prepare_extent_to_map+0xe1b/0x16f0 fs/ext4/inode.c:2740 ext4_do_writepages+0xbca/0x46e0 fs/ext4/inode.c:2881 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3029 do_writepages+0x32e/0x550 mm/page-writeback.c:2554 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1762 writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2054 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241 wb_check_old_data_flush fs/fs-writeback.c:2345 [inline] wb_do_writeback fs/fs-writeback.c:2398 [inline] wb_workfn+0xb4c/0xf50 fs/fs-writeback.c:2426 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245