syzbot

watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [syz.0.498:6384]
Modules linked in:
irq event stamp: 1036815
hardirqs last  enabled at (1036814): [<ffff8000083b91b8>] seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline]
hardirqs last  enabled at (1036814): [<ffff8000083b91b8>] timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
hardirqs last  enabled at (1036814): [<ffff8000083b91b8>] timekeeping_get_ns+0x124/0x3b8 kernel/time/timekeeping.c:388
hardirqs last disabled at (1036815): [<ffff800011958a70>] __el1_irq arch/arm64/kernel/entry-common.c:468 [inline]
hardirqs last disabled at (1036815): [<ffff800011958a70>] el1_interrupt+0x24/0x54 arch/arm64/kernel/entry-common.c:486
softirqs last  enabled at (1414): [<ffff8000081a967c>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (1414): [<ffff8000081a967c>] handle_softirqs+0xaf8/0xc6c kernel/softirq.c:624
softirqs last disabled at (6629): [<ffff800008020164>] __do_softirq+0x14/0x20 kernel/softirq.c:630
CPU: 1 PID: 6384 Comm: syz.0.498 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 42400005 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __sanitizer_cov_trace_cmp4+0xac/0xb0 kernel/kcov.c:288
lr : cake_heapify+0x234/0x530 net/sched/sch_cake.c:1497
sp : ffff800008016fd0
x29: ffff800008016fe0 x28: dfff800000000000 x27: 00000000000198d0
x26: 0000000000001e04 x25: 0000000000000000 x24: ffff000101d7b240
x23: dfff800000000000 x22: 0000000000000f01 x21: 0000000000000000
x20: ffff0000da4c02d0 x19: 0000000000000f01 x18: ffff800011abbcc0
x17: ffff8000181fa000 x16: ffff8000082d22e0 x15: ffff800017cdafc0
x14: ffff0000f7072658 x13: 1ffff00002a180b1 x12: 0000000000ff0100
x11: ff0080000ffc9bb4 x10: 0000000000000000 x9 : ffff0000f7071bc0
x8 : ffff80000ffc9bb4 x7 : ffff8000083b95c4 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000002 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 __sanitizer_cov_trace_cmp4+0xac/0xb0 kernel/kcov.c:288
 cake_drop net/sched/sch_cake.c:1575 [inline]
 cake_enqueue+0x32dc/0x6670 net/sched/sch_cake.c:1948
 qdisc_enqueue include/net/sch_generic.h:816 [inline]
 netem_dequeue+0xa74/0x107c net/sched/sch_netem.c:737
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x1c4/0x1368 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3970 [inline]
 __dev_queue_xmit+0xc18/0x309c net/core/dev.c:4312
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 tipc_l2_send_msg+0x29c/0x35c net/tipc/bearer.c:518
 tipc_bearer_xmit_skb+0x244/0x384 net/tipc/bearer.c:577
 tipc_disc_timeout+0x4c8/0x608 net/tipc/discover.c:338
 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x460/0x6bc kernel/time/timer.c:1820
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1833
 handle_softirqs+0x318/0xc6c kernel/softirq.c:596
 __do_softirq+0x14/0x20 kernel/softirq.c:630
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:897
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:477 [inline]
 __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:679
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691
 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
 el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
 folio_memcg_lock+0xf8/0x1fc mm/memcontrol.c:2113
 lock_page_memcg+0x48/0x58 mm/memcontrol.c:2137
 page_add_file_rmap+0x158/0xc40 mm/rmap.c:1293
 do_set_pte+0x34c/0x49c mm/memory.c:4424
 finish_fault+0x560/0x65c mm/memory.c:4499
 do_read_fault mm/memory.c:4635 [inline]
 do_fault mm/memory.c:4760 [inline]
 handle_pte_fault mm/memory.c:5031 [inline]
 __handle_mm_fault mm/memory.c:5173 [inline]
 handle_mm_fault+0x1ae4/0x2fd4 mm/memory.c:5294
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x338/0x798 mm/gup.c:1250
 populate_vma_page_range+0x1f4/0x298 mm/gup.c:1607
 __mm_populate+0x208/0x330 mm/gup.c:1721
 mm_populate include/linux/mm.h:2837 [inline]
 vm_mmap_pgoff+0x1cc/0x284 mm/util.c:525
 ksys_mmap_pgoff+0xd0/0x5a0 mm/mmap.c:1482
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585