rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1095/1:b..l P5142/1:b..l rcu: (detected by 1, t=10502 jiffies, g=10297, q=898 ncpus=2) task:udevd state:R running task stack:25160 pid:5142 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfa/0x110 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11f/0x190 kernel/sched/wait.c:213 sock_def_readable+0x1e1/0x430 net/core/sock.c:3329 __netlink_sendskb net/netlink/af_netlink.c:1270 [inline] netlink_sendskb+0x9b/0x130 net/netlink/af_netlink.c:1276 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595 ___sys_sendmsg+0x220/0x290 net/socket.c:2649 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2687 [inline] __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685 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: 0033:0x7f588e2a7407 RSP: 002b:00007ffc1556e080 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f588ea58880 RCX: 00007f588e2a7407 RDX: 0000000000000000 RSI: 00007ffc1556e0e0 RDI: 0000000000000004 RBP: 0000557dce304a90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b2 R13: 0000557dce2f19e0 R14: 0000000000000000 R15: 0000000000000000 task:kworker/u4:7 state:R running task stack:21712 pid:1095 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7010 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:PagePoisoned include/linux/page-flags.h:297 [inline] RIP: 0010:page_to_nid include/linux/mm.h:1636 [inline] RIP: 0010:page_zone include/linux/mm.h:1850 [inline] RIP: 0010:folio_zone include/linux/mm.h:1860 [inline] RIP: 0010:zone_stat_mod_folio include/linux/vmstat.h:439 [inline] RIP: 0010:folio_clear_dirty_for_io+0x557/0xc30 mm/page-writeback.c:2932 Code: cd ff 49 bf 00 00 00 00 00 fc ff df 4d 85 f6 75 0e e8 3d dc cd ff 43 80 3c 3c 00 75 0f eb 15 e8 2f dc cd ff fb 43 80 3c 3c 00 <74> 08 48 89 df e8 3f 83 26 00 4c 8b 3b 48 c7 c7 ff ff ff ff 4c 89 RSP: 0018:ffffc9000455ece0 EFLAGS: 00000246 RAX: ffffffff81b7b9a1 RBX: ffffea0001cf5040 RCX: ffff888023529e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000455ede8 R08: ffffffff90d855c7 R09: 1ffffffff21b0ab8 R10: dffffc0000000000 R11: fffffbfff21b0ab9 R12: 1ffffd400039ea08 R13: 0000000000000001 R14: 0000000000000200 R15: dffffc0000000000 mpage_submit_folio+0x7d/0x3c0 fs/ext4/inode.c:1884 mpage_map_and_submit_buffers fs/ext4/inode.c:2149 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2288 [inline] ext4_do_writepages+0x1d01/0x38d0 fs/ext4/inode.c:2713 ext4_writepages+0x1a8/0x2f0 fs/ext4/inode.c:2802 do_writepages+0x3a2/0x600 mm/page-writeback.c:2575 __writeback_single_inode+0x153/0xee0 fs/fs-writeback.c:1625 writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1916 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1987 wb_writeback+0x464/0xba0 fs/fs-writeback.c:2097 wb_check_old_data_flush fs/fs-writeback.c:2201 [inline] wb_do_writeback fs/fs-writeback.c:2254 [inline] wb_workfn+0xabc/0xe20 fs/fs-writeback.c:2282 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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 rcu: rcu_preempt kthread starved for 10568 jiffies! g10297 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:27496 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 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 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6019 Comm: syz.0.31 Not tainted 6.6.94-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x82/0x90 kernel/kcov.c:315 Code: 8d 52 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 05 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 04 24 RSP: 0018:ffffc90000007810 EFLAGS: 00000006 RAX: ffffffff813abf63 RBX: 1ffff92000000f29 RCX: 0000000000010000 RDX: ffff8880264e9e00 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffff8880264e9e00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000010000 R12: ffffc90000008000 R13: 1ffff92000000f2b R14: ffffc90000000000 R15: ffffc90000007948 FS: 00007fb2962ce6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc9e8581178 CR3: 000000005cfcb000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_stack arch/x86/include/asm/stacktrace.h:58 [inline] stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline] deref_stack_reg+0x93/0x240 arch/x86/kernel/unwind_orc.c:403 unwind_next_frame+0x1789/0x2970 arch/x86/kernel/unwind_orc.c:648 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:3485 [inline] slab_alloc mm/slub.c:3493 [inline] __kmem_cache_alloc_lru mm/slub.c:3500 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509 __sigqueue_alloc+0x40c/0x520 kernel/signal.c:438 __send_signal_locked+0x22f/0xe00 kernel/signal.c:1130 do_send_sig_info kernel/signal.c:1312 [inline] group_send_sig_info+0x1fa/0x260 kernel/signal.c:1462 do_bpf_send_signal+0x7f/0x190 kernel/trace/bpf_trace.c:836 irq_work_single+0xd5/0x230 kernel/irq_work.c:221 irq_work_run_list kernel/irq_work.c:252 [inline] irq_work_run+0x156/0x2e0 kernel/irq_work.c:261 __sysvec_irq_work+0x98/0x380 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x9c/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:196 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 f3 0f 1e fa 89 f6 31 d2 e9 37 7c 19 03 0f 1f 80 00 00 00 RSP: 0018:ffffc90003787cb8 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: 0000000000000200 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: ffffc90003787c27 R09: 1ffff920006f0f84 R10: dffffc0000000000 R11: fffff520006f0f85 R12: ffff8880b8e35201 R13: dffffc0000000000 R14: ffff8880b8e35290 R15: 0000000000000020 __apic_send_IPI_self arch/x86/include/asm/apic.h:454 [inline] arch_irq_work_raise+0x68/0x70 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x99/0x140 kernel/irq_work.c:124 bpf_send_signal_common+0x2b6/0x420 kernel/trace/bpf_trace.c:875 ____bpf_send_signal kernel/trace/bpf_trace.c:884 [inline] bpf_send_signal+0x19/0x20 kernel/trace/bpf_trace.c:882 bpf_prog_7ba5217f62dcd359+0x40/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 __traceiter_sys_enter+0x2a/0x40 include/trace/events/syscalls.h:18 trace_sys_enter+0x69/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb29532ab19 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007fb2962cdb40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007fb2955b5fa8 RCX: 00007fb29532ab19 RDX: 00007fb2962cdb40 RSI: 00007fb2962cdc70 RDI: 0000000000000011 RBP: 00007fb2955b5fa0 R08: 0000000000745a08 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 00007fb2955b5fac R13: 0000000000000000 R14: 00007ffc56169d30 R15: 00007ffc56169e18 sched: RT throttling activated