syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8098/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=26185, q=361 ncpus=2)
task:sed             state:R  running task     stack:23976 pid:8098  ppid:8096   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:in_irqentry_text kernel/stacktrace.c:379 [inline]
RIP: 0010:filter_irq_stacks+0x65/0x90 kernel/stacktrace.c:395
Code: 00 49 8b 04 de 48 3d e0 01 80 8a 0f 93 c1 48 3d f0 15 80 8a 0f 92 c2 84 d1 75 27 48 3d 70 0e 79 8a 0f 92 c1 48 3d 7b 0e 79 8a <0f> 93 c0 08 c8 74 11 48 ff c3 49 83 c7 08 49 39 dc 75 ae 44 89 e3
RSP: 0018:ffffc900042df5d8 EFLAGS: 00000293
RAX: ffffffff8151205a RBX: 0000000000000007 RCX: 0000000000000001
RDX: 0000000000002801 RSI: 000000000000000d RDI: ffffc900042df6a0
RBP: 0000000000002800 R08: ffffffff8e4a8e2f R09: 1ffffffff1c951c5
R10: dffffc0000000000 R11: fffffbfff1c951c6 R12: 000000000000000d
R13: dffffc0000000000 R14: ffffc900042df6a0 R15: ffffc900042df6d8
 __stack_depot_save+0x1f/0x630 lib/stackdepot.c:377
 save_stack+0x105/0x1f0 mm/page_owner.c:129
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd74e8dd6c5
RSP: 002b:00007ffd805813f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fd74e9defe8 RCX: 00007fd74e8dd6c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd74e9dd680 R15: 00007fd74e9df000
 </TASK>
rcu: rcu_preempt kthread starved for 10213 jiffies! g26185 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:26568 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:preempt_count_add+0x6a/0x1a0 kernel/sched/core.c:5848
Code: a8 7e 48 c7 c0 80 04 eb 96 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 e6 00 00 00 83 3d ef 86 8f 15 00 75 11 65 8b 05 2e 38 a8 7e <0f> b6 c0 3d f5 00 00 00 73 58 65 8b 05 1d 38 a8 7e 25 ff ff ff 7f
RSP: 0018:ffffc900000073b8 EFLAGS: 00000246
RAX: 0000000080000102 RBX: 1ffff92000000e95 RCX: ffffffff96eb0403
RDX: ffffffff8ca93440 RSI: 0000000000000002 RDI: 0000000000000001
RBP: 0000000000000002 R08: ffffc90000007570 R09: 0000000000000006
R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900000074a8
R13: dffffc0000000000 R14: ffffc900000074e0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ad7691cea CR3: 0000000076588000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 unwind_next_frame+0xbe/0x2970 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 kmem_cache_alloc_node+0x150/0x330 mm/slub.c:3540
 __alloc_skb+0x108/0x2c0 net/core/skbuff.c:643
 __netdev_alloc_skb+0x10c/0x500 net/core/skbuff.c:717
 netdev_alloc_skb include/linux/skbuff.h:3272 [inline]
 dev_alloc_skb include/linux/skbuff.h:3285 [inline]
 __ieee80211_beacon_get+0xe17/0x1600 net/mac80211/tx.c:5447
 ieee80211_beacon_get_tim+0xb8/0x560 net/mac80211/tx.c:5569
 ieee80211_beacon_get include/net/mac80211.h:5440 [inline]
 mac80211_hwsim_beacon_tx+0x3c7/0x780 drivers/net/wireless/virtual/mac80211_hwsim.c:2265
 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:766
 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:802
 mac80211_hwsim_beacon+0xbb/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2295
 __run_hrtimer kernel/time/hrtimer.c:1750 [inline]
 __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1831
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 f4 38 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c2
RAX: cce27aab469e3c00 RBX: ffffffff8161981b RCX: cce27aab469e3c00
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f40
RBP: ffffffff8ca07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: ffffffff8e4a8e28
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952688
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 rest_init+0x2e2/0x300 init/main.c:744
 arch_call_rest_init+0xe/0x10 init/main.c:841
 start_kernel+0x459/0x4e0 init/main.c:1086
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>