syzbot

watchdog: BUG: soft lockup - CPU#1 stuck for 26s! [syz.6.948:8117]
Modules linked in:
irq event stamp: 1135179
hardirqs last  enabled at (1135178): [<ffff8000083c23d4>] seqcount_lockdep_reader_access include/linux/seqlock.h:104 [inline]
hardirqs last  enabled at (1135178): [<ffff8000083c23d4>] timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
hardirqs last  enabled at (1135178): [<ffff8000083c23d4>] timekeeping_get_ns+0x124/0x3b4 kernel/time/timekeeping.c:388
hardirqs last disabled at (1135179): [<ffff800011a4ecd4>] __el1_irq arch/arm64/kernel/entry-common.c:468 [inline]
hardirqs last disabled at (1135179): [<ffff800011a4ecd4>] el1_interrupt+0x24/0x54 arch/arm64/kernel/entry-common.c:486
softirqs last  enabled at (5732): [<ffff8000081acd08>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (5732): [<ffff8000081acd08>] handle_softirqs+0xaec/0xc60 kernel/softirq.c:624
softirqs last disabled at (7239): [<ffff800008020e4c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
CPU: 1 PID: 8117 Comm: syz.6.948 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
pstate: 42400005 (nZcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : check_kcov_mode kernel/kcov.c:182 [inline]
pc : write_comp_data kernel/kcov.c:245 [inline]
pc : __sanitizer_cov_trace_const_cmp4+0x58/0xb0 kernel/kcov.c:313
lr : cake_heapify+0x1b0/0x530 net/sched/sch_cake.c:1494
sp : ffff800008016fc0
x29: ffff800008016fe0 x28: ffff0000df0942d8 x27: 00000000000198d0
x26: 00000000000006fa x25: 0000000000000000 x24: 000000000000037d
x23: dfff800000000000 x22: 000000000000037d x21: 0000000000000000
x20: ffff0000df0902d0 x19: 000000000000037d x18: ffff800011babf60
x17: ffff800018381000 x16: ffff8000082d9e48 x15: ffff800017e62000
x14: 0000000000000001 x13: 1ffff00002a48071 x12: 0000000000ff0100
x11: ff00800010078d90 x10: 0000000000000000 x9 : ffff0000cf143800
x8 : ffff800010078d90 x7 : ffff8000083c27dc x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000002 x1 : 000000000000037d x0 : 0000000000000fff
Call trace:
 check_kcov_mode kernel/kcov.c:182 [inline]
 write_comp_data kernel/kcov.c:245 [inline]
 __sanitizer_cov_trace_const_cmp4+0x58/0xb0 kernel/kcov.c:313
 cake_drop net/sched/sch_cake.c:1575 [inline]
 cake_enqueue+0x3378/0x68f8 net/sched/sch_cake.c:1949
 qdisc_enqueue include/net/sch_generic.h:854 [inline]
 netem_dequeue+0xa40/0x1048 net/sched/sch_netem.c:736
 dequeue_skb net/sched/sch_generic.c:295 [inline]
 qdisc_restart net/sched/sch_generic.c:400 [inline]
 __qdisc_run+0x1cc/0x133c net/sched/sch_generic.c:418
 __dev_xmit_skb net/core/dev.c:3995 [inline]
 __dev_queue_xmit+0xc40/0x3118 net/core/dev.c:4337
 dev_queue_xmit include/linux/netdevice.h:3051 [inline]
 tipc_l2_send_msg+0x29c/0x35c net/tipc/bearer.c:518
 tipc_bearer_xmit_skb+0x240/0x380 net/tipc/bearer.c:577
 tipc_disc_timeout+0x4d8/0x628 net/tipc/discover.c:338
 call_timer_fn+0x1b8/0x95c kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x478/0x6f0 kernel/time/timer.c:2023
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:2036
 handle_softirqs+0x318/0xc60 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/0x438 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
 atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline]
 __page_table_check_zero+0x17c/0x2b0 mm/page_table_check.c:154
 page_table_check_free include/linux/page_table_check.h:46 [inline]
 free_pages_prepare mm/page_alloc.c:1487 [inline]
 free_pcp_prepare mm/page_alloc.c:1536 [inline]
 free_unref_page_prepare+0x9e4/0xaf0 mm/page_alloc.c:3413
 free_unref_page+0x7c/0x3a0 mm/page_alloc.c:3508
 free_the_page mm/page_alloc.c:781 [inline]
 __free_pages+0x1a0/0x1cc mm/page_alloc.c:5746
 __free_slab+0x104/0x294 mm/slub.c:2021
 free_slab mm/slub.c:2036 [inline]
 discard_slab+0x58/0xd4 mm/slub.c:2042
 __unfreeze_partials+0x150/0x190 mm/slub.c:2591
 put_cpu_partial+0x18c/0x1f8 mm/slub.c:2667
 __slab_free+0x1a4/0x268 mm/slub.c:3564
 do_slab_free mm/slub.c:3641 [inline]
 ___cache_free+0x168/0x198 mm/slub.c:3694
 qlink_free+0x5c/0xa0 mm/kasan/quarantine.c:168
 qlist_free_all+0x3c/0xcc mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x124/0x130 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x2c/0x88 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x74/0x430 mm/slab.h:737
 kmem_cache_alloc_bulk+0x41c/0x4e4 mm/slub.c:3880
 mt_alloc_bulk lib/maple_tree.c:159 [inline]
 mas_alloc_nodes+0x484/0x754 lib/maple_tree.c:1301
 mas_node_count_gfp lib/maple_tree.c:1361 [inline]
 mas_preallocate+0x13c/0x310 lib/maple_tree.c:5809
 __vma_adjust+0x25c/0x1724 mm/mmap.c:724
 vma_adjust include/linux/mm.h:2810 [inline]
 __split_vma+0x324/0x444 mm/mmap.c:-1
 split_vma+0xa0/0xf8 mm/mmap.c:2424
 mprotect_fixup+0x3b8/0x5c4 mm/mprotect.c:623
 do_mprotect_pkey mm/mprotect.c:792 [inline]
 __do_sys_mprotect mm/mprotect.c:819 [inline]
 __se_sys_mprotect mm/mprotect.c:816 [inline]
 __arm64_sys_mprotect+0x5e4/0xa0c mm/mprotect.c:816
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x128 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