rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5992/1:b..l rcu: (detected by 1, t=10503 jiffies, g=14805, q=1022 ncpus=2) task:udevd state:R running task stack:23616 pid:5992 tgid:5992 ppid:5637 task_flags:0x440040 flags:0x00080800 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0x7e0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b a2 26 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 48 f3 0e 0f 82 a4 02 00 00 8b 35 ce 7b f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd a1 26 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc90002f3e240 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000003 RDX: 0000000000000000 RSI: ffffffff8defdaa7 RDI: ffffffff8c1c4180 RBP: ffffffff8e7e5620 R08: 000000001b15e27f R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __set_page_owner+0x8c/0x540 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490 alloc_pages_noprof mm/mempolicy.c:2581 [inline] folio_alloc_noprof+0x22/0x250 mm/mempolicy.c:2591 filemap_alloc_folio_noprof.part.0+0x377/0x450 mm/filemap.c:1014 filemap_alloc_folio_noprof+0x5e/0x80 mm/filemap.c:1015 ractl_alloc_folio+0x1d/0x100 mm/readahead.c:189 page_cache_ra_unbounded+0x355/0xa10 mm/readahead.c:277 do_page_cache_ra+0x10c/0x160 mm/readahead.c:334 page_cache_ra_order+0xc2f/0xf10 mm/readahead.c:538 page_cache_async_ra+0x7bb/0xd30 mm/readahead.c:700 filemap_readahead.isra.0+0x11c/0x190 mm/filemap.c:2664 filemap_get_pages+0xa8a/0x2030 mm/filemap.c:2710 filemap_read+0x3b5/0x10a0 mm/filemap.c:2806 generic_file_read_iter+0x344/0x450 mm/filemap.c:2998 ext4_file_read_iter+0x1dd/0x6c0 fs/ext4/file.c:147 __kernel_read+0x397/0xac0 fs/read_write.c:532 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28 ima_calc_file_hash_tfm+0x25e/0x350 security/integrity/ima/ima_crypto.c:222 ima_calc_file_hash+0x1e3/0x380 security/integrity/ima/ima_crypto.c:280 ima_collect_measurement+0x94f/0xb30 security/integrity/ima/ima_api.c:300 process_measurement+0xdfe/0x2350 security/integrity/ima/ima_main.c:425 ima_bprm_check+0x10d/0x170 security/integrity/ima/ima_main.c:607 security_bprm_check+0xd7/0x1e0 security/security.c:820 search_binary_handler fs/exec.c:1654 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve fs/exec.c:1748 [inline] bprm_execve+0x845/0x1740 fs/exec.c:1724 do_execveat_common.isra.0+0x4a5/0x580 fs/exec.c:1846 __do_sys_execve fs/exec.c:1930 [inline] __se_sys_execve fs/exec.c:1924 [inline] __x64_sys_execve+0x93/0xd0 fs/exec.c:1924 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6c412f2107 RSP: 002b:00007fffdcf2c038 EFLAGS: 00000202 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00005642931fa140 RCX: 00007f6c412f2107 RDX: 00005642ce827b10 RSI: 00007fffdcf2c150 RDI: 00007fffdcf2c950 RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000202 R12: 00005642ce827b10 R13: 00007fffdcf2c150 R14: 000000000000000d R15: 0000000000000009 rcu: rcu_preempt kthread starved for 4233 jiffies! g14805 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 5990 Comm: syz.4.21 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] RIP: 0010:rcu_is_watching+0x63/0xc0 kernel/rcu/tree.c:752 Code: 48 c1 ea 03 80 3c 02 00 75 5c 48 03 1c ed 20 69 1d 8e 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 0f b6 14 02 48 89 d8 <83> e0 07 83 c0 03 38 d0 7c 04 84 d2 75 24 8b 03 c1 e8 02 83 e0 01 RSP: 0018:ffffc90000a085b0 EFLAGS: 00000a02 RAX: ffff8880b8533da8 RBX: ffff8880b8533da8 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8c1c4100 RDI: ffffffff8e1d6928 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000200 R11: 000000000000aa1c R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812446d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005642ce8ae6d0 CR3: 0000000073e57000 CR4: 00000000003526f0 Call Trace: trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2f9/0x370 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_node_noprof+0x25a/0x6f0 mm/slub.c:4950 kmalloc_reserve+0x148/0x350 net/core/skbuff.c:613 __alloc_skb+0x185/0x710 net/core/skbuff.c:713 __netdev_alloc_skb+0x7a/0x960 net/core/skbuff.c:775 netdev_alloc_skb include/linux/skbuff.h:3499 [inline] dev_alloc_skb include/linux/skbuff.h:3512 [inline] __ieee80211_beacon_get+0xba1/0x1ee0 net/mac80211/tx.c:5725 ieee80211_beacon_get_tim+0xa6/0x280 net/mac80211/tx.c:5847 ieee80211_beacon_get include/net/mac80211.h:5848 [inline] mac80211_hwsim_beacon_tx+0x4d7/0xa00 drivers/net/wireless/virtual/mac80211_hwsim.c:2497 __iterate_interfaces+0x2e6/0x650 net/mac80211/util.c:772 ieee80211_iterate_active_interfaces_atomic+0x71/0x1b0 net/mac80211/util.c:808 mac80211_hwsim_beacon+0x105/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2531 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2011 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc90002f6f650 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fc2d8d RDX: ffff88807b1aca00 RSI: ffffffff81fc2d67 RDI: ffff88807b1aca00 RBP: ffff8880b8443320 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed1017088665 R14: 0000000000000001 R15: ffff8880b853c5c0 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline] tlb_flush_mmu mm/mmu_gather.c:423 [inline] tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549 exit_mmap+0x454/0xa10 mm/mmap.c:1313 __mmput+0x12a/0x410 kernel/fork.c:1178 mmput+0x67/0x80 kernel/fork.c:1201 exit_mm kernel/exit.c:582 [inline] do_exit+0x8b2/0x2af0 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119 get_signal+0x20ff/0x2210 kernel/signal.c:3037 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x8b/0x4f0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x706/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f094a79ce59 Code: Unable to access opcode bytes at 0x7f094a79ce2f. RSP: 002b:00007ffddde980a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffff92 RBX: 000000000001cee3 RCX: 00007f094a79ce59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f094aa15fac RBP: 0000000000000bea R08: 0000000000000001 R09: 0000000000000000 R10: 00007ffddde981b0 R11: 0000000000000246 R12: 00007ffddde981d0 R13: 00007f094aa15fac R14: 000000000001dacd R15: 00007ffddde981b0