watchdog: BUG: soft lockup - CPU#1 stuck for 120s! [syz.6.521:8543] Modules linked in: irq event stamp: 10193081 hardirqs last enabled at (10193080): [] irqentry_exit+0x59e/0x620 kernel/entry/common.c:242 hardirqs last disabled at (10193081): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (10083696): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (10083696): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (10083696): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 softirqs last disabled at (10083699): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (10083699): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (10083699): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 CPU: 1 UID: 0 PID: 8543 Comm: syz.6.521 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 85 f4 0d 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 01 02 7b 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 3e 95 73 RSP: 0018:ffffc90000a08120 EFLAGS: 00000292 RAX: 6dad609169083500 RBX: 0000000000000246 RCX: 0000000000000103 RDX: 00000000d0b2f21e RSI: ffffffff8e16b7af RDI: ffffffff8c27d100 RBP: 0000000000000000 R08: ffffffff81d17df2 R09: ffffffff8e75e5e0 R10: dffffc0000000000 R11: fffff91ffffb3405 R12: 0000000000000002 R13: ffffffff8e75e5e0 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fdecbae66c0(0000) GS:ffff888125557000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005618d4ae6950 CR3: 0000000068fb8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] trace_call_bpf+0xe3/0xb70 kernel/trace/bpf_trace.c:-1 perf_trace_run_bpf_submit+0x78/0x170 kernel/events/core.c:11329 do_perf_trace_lock include/trace/events/lock.h:50 [inline] perf_trace_lock+0x32d/0x410 include/trace/events/lock.h:50 __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x392/0x3d0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:322 [inline] rcu_read_unlock include/linux/rcupdate.h:881 [inline] class_rcu_destructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4873 dst_alloc+0x105/0x170 net/core/dst.c:90 ip6_dst_alloc net/ipv6/route.c:342 [inline] icmp6_dst_alloc+0x75/0x440 net/ipv6/route.c:3336 ndisc_send_skb+0x44a/0x1670 net/ipv6/ndisc.c:491 addrconf_rs_timer+0x395/0x6d0 net/ipv6/addrconf.c:4041 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:bytes_is_nonzero mm/kasan/generic.c:98 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x97/0x2c0 mm/kasan/generic.c:200 Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 3d 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 9e 01 00 00 49 ff c3 48 ff c3 75 ee e9 1d 01 00 00 44 89 dd RSP: 0018:ffffc900045bf0e8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: fffffffffffffffe RCX: ffffffff81cfa6df RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffe8ffffd97024 RBP: 0000000000000000 R08: ffffe8ffffd9702b R09: 1ffffd1ffffb2e05 R10: dffffc0000000000 R11: fffff91ffffb2e04 R12: 0000000000000002 R13: dffffc0000000000 R14: fffff91ffffb2e06 R15: 1ffffd1ffffb2e04 __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 perf_trace_buf_alloc+0x1bf/0x280 kernel/trace/trace_event_perf.c:419 do_perf_trace_lock include/trace/events/lock.h:50 [inline] perf_trace_lock+0x1a0/0x410 include/trace/events/lock.h:50 __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x392/0x3d0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:322 [inline] rcu_read_unlock include/linux/rcupdate.h:881 [inline] class_rcu_destructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3131 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3251 context_switch kernel/sched/core.c:5301 [inline] __schedule+0x15e5/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 futex_do_wait kernel/futex/waitwake.c:358 [inline] __futex_wait+0x1ee/0x420 kernel/futex/waitwake.c:687 futex_wait+0x119/0x380 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+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: 0033:0x7fdecab9c819 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:00007fdecbae60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fdecae15fa8 RCX: 00007fdecab9c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdecae15fa8 RBP: 00007fdecae15fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdecae16038 R14: 00007ffd03020bd0 R15: 00007ffd03020cb8 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 58 Comm: kworker/u8:4 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+0xcea/0x12c0 kernel/smp.c:877 Code: 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 0b 00 eb e4 44 RSP: 0018:ffffc900015f6220 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170e813d RCX: ffff88801cbb8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900015f6350 R08: ffff888035c2e147 R09: 1ffff11006b85c28 R10: dffffc0000000000 R11: ffffffff81787350 R12: ffff8880b87409e8 R13: dffffc0000000000 R14: ffff8880b863c000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125457000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055802c28da38 CR3: 000000007ba0e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 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