watchdog: BUG: soft lockup - CPU#1 stuck for 123s! [syz.0.2499:15266] Modules linked in: irq event stamp: 12769357 hardirqs last enabled at (12769356): [] irqentry_exit+0x74/0x90 kernel/entry/common.c:214 hardirqs last disabled at (12769357): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1052 softirqs last enabled at (12440116): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (12440116): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (12440116): [] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 softirqs last disabled at (12440119): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (12440119): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (12440119): [] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 CPU: 1 UID: 0 PID: 15266 Comm: syz.0.2499 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 5b 1d d1 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90000a085f8 EFLAGS: 00000206 RAX: 6a06321db8676000 RBX: 0000000000000000 RCX: 6a06321db8676000 RDX: 0000000000000000 RSI: ffffffff8d8f55b7 RDI: ffffffff8bbf08e0 RBP: ffffffff81738c45 R08: 0000000000000000 R09: ffffffff81738c45 R10: ffffc90000a082c8 R11: ffffffff81ac2e10 R12: 0000000000000002 R13: ffffffff8df3d6e0 R14: 0000000000000000 R15: 0000000000000246 FS: 00007f52a84896c0(0000) GS:ffff888126239000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f52a84890e8 CR3: 00000000478f0000 CR4: 00000000003526f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2543 [inline] slab_free mm/slub.c:6642 [inline] kmem_cache_free+0x19b/0x690 mm/slub.c:6752 mac80211_hwsim_beacon_tx+0x3f0/0x860 drivers/net/wireless/virtual/mac80211_hwsim.c:2365 __iterate_interfaces+0x2ab/0x590 net/mac80211/util.c:761 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:797 mac80211_hwsim_beacon+0xbb/0x180 drivers/net/wireless/virtual/mac80211_hwsim.c:2395 __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858 handle_softirqs+0x286/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__asan_memset+0x8/0x50 mm/kasan/shadow.c:83 Code: 00 e9 bc e4 ff ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 56 53 <48> 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 e8 RSP: 0018:ffffc900030375a0 EFLAGS: 00000246 RAX: ffffc90003037640 RBX: ffffe8ffffd2daf0 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90003037780 RBP: ffffc90003037828 R08: ffffc9000303773f R09: 0000000000000000 R10: ffffc90003037640 R11: fffff52000606ee8 R12: 000000000000002c R13: ffffe8ffffde4000 R14: ffffc90003037640 R15: dffffc0000000000 perf_tp_event+0xcb/0x1380 kernel/events/core.c:10992 perf_trace_run_bpf_submit+0xee/0x170 kernel/events/core.c:10936 do_perf_trace_lock include/trace/events/lock.h:50 [inline] perf_trace_lock+0x2f8/0x3b0 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+0x3b2/0x3e0 kernel/locking/lockdep.c:5879 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] wp_page_copy mm/memory.c:3781 [inline] do_wp_page+0x1d1d/0x5800 mm/memory.c:4141 handle_pte_fault mm/memory.c:6211 [inline] __handle_mm_fault+0x1033/0x5400 mm/memory.c:6336 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6505 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f52a745f12b Code: 00 74 24 80 3d c8 65 eb 00 00 0f b6 35 be 65 eb 00 75 4c 80 3d b9 65 eb 00 00 75 43 40 84 f6 75 3e 66 0f 1f 44 00 00 48 89 ef 70 fa ff ff 8b 45 0c 85 c0 75 35 48 8d 75 0c b9 40 42 0f 00 ba RSP: 002b:00007f52a84890f0 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 00007f52a77e6098 RCX: 00007f52a758f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f52a77e6090 RBP: 00007f52a77e6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f52a77e6128 R14: 00007ffface4c9b0 R15: 00007ffface4ca98 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 50 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd4b/0x12d0 kernel/smp.c:877 Code: 00 00 00 00 fc ff df 75 07 e8 91 6f 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 75 6f 0b 00 e4 44 89 e1 80 e1 07 80 c1 03 38 c1 7c e2 4c 89 e7 e8 ee 30 71 RSP: 0018:ffffc90000bb6040 EFLAGS: 00000293 RAX: ffffffff81b4944b RBX: 1ffff11017127ffd RCX: ffff88801dea9e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000bb61c0 R08: ffff88803388aa47 R09: 1ffff11006711548 R10: dffffc0000000000 R11: ffffed1006711549 R12: ffff8880b893ffe8 R13: dffffc0000000000 R14: ffff8880b883b240 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888126139000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdba04dedd0 CR3: 000000007e38c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000200000000300 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:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline] flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1471 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101 page_vma_mkclean_one+0x406/0x740 mm/rmap.c:1041 page_mkclean_one+0x1c0/0x280 mm/rmap.c:1082 __rmap_walk_file+0x467/0x620 mm/rmap.c:2918 rmap_walk mm/rmap.c:2962 [inline] folio_mkclean+0x297/0x390 mm/rmap.c:1114 folio_clear_dirty_for_io+0x1f5/0x880 mm/page-writeback.c:2938 mpage_submit_folio+0x86/0x2b0 fs/ext4/inode.c:2061 mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2191 mpage_prepare_extent_to_map+0xe6c/0x16e0 fs/ext4/inode.c:2736 ext4_do_writepages+0xba0/0x4610 fs/ext4/inode.c:2877 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025 do_writepages+0x32e/0x550 mm/page-writeback.c:2604 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2086 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2197 wb_check_old_data_flush fs/fs-writeback.c:2301 [inline] wb_do_writeback fs/fs-writeback.c:2354 [inline] wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2382 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245