rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9496/1:b..l rcu: (detected by 0, t=10502 jiffies, g=33001, q=1169695 ncpus=2) task:kworker/u8:10 state:R running task stack:18712 pid:9496 tgid:9496 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:6954 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7e/0xb0 kernel/rcu/tree.c:738 rcu_read_unlock include/linux/rcupdate.h:878 [inline] blk_mq_run_hw_queue+0x9be/0xae0 block/blk-mq.c:2243 blk_mq_flush_plug_list+0x1127/0x1890 block/blk-mq.c:2798 blk_add_rq_to_plug+0x19c/0x480 block/blk-mq.c:1290 blk_mq_submit_bio+0x132f/0x2500 block/blk-mq.c:3031 __submit_bio+0x1c1/0x560 block/blk-core.c:615 __submit_bio_noacct_mq block/blk-core.c:696 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:725 ext4_io_submit fs/ext4/page-io.c:377 [inline] io_submit_add_bh fs/ext4/page-io.c:418 [inline] ext4_bio_write_folio+0x123a/0x1d70 fs/ext4/page-io.c:560 mpage_submit_folio+0x1af/0x230 fs/ext4/inode.c:1921 mpage_process_page_bufs+0x6c9/0x8d0 fs/ext4/inode.c:2034 mpage_prepare_extent_to_map+0xec7/0x1c80 fs/ext4/inode.c:2535 ext4_do_writepages+0xc55/0x3d20 fs/ext4/inode.c:2677 ext4_writepages+0x213/0x3c0 fs/ext4/inode.c:2813 do_writepages+0x35d/0x870 mm/page-writeback.c:2683 __writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1658 writeback_sb_inodes+0x80c/0x1370 fs/fs-writeback.c:1954 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2025 wb_writeback+0x42f/0xbd0 fs/fs-writeback.c:2136 wb_check_old_data_flush fs/fs-writeback.c:2240 [inline] wb_do_writeback fs/fs-writeback.c:2293 [inline] wb_workfn+0xba1/0x1090 fs/fs-writeback.c:2321 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10011 jiffies! g33001 f0x2 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:24848 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 2861 Comm: kworker/R-bat_e Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: bat_events batadv_dat_purge 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:149 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:256 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:212 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 cc cc cc cc f3 0f 1e fa 89 f6 31 d2 e9 63 4c b5 03 0f 1f RSP: 0018:ffffc90000a18bf0 EFLAGS: 00000046 RAX: 000000000008fae8 RBX: 0000000000000020 RCX: 0000000000000838 RDX: 0000000000000000 RSI: 000000000008fae8 RDI: 0000000000000838 RBP: 000000000008fae8 R08: ffffffff81857a39 R09: 1ffffffff203a235 R10: dffffc0000000000 R11: ffffffff813ec4e0 R12: 00000000008faaf8 R13: dffffc0000000000 R14: 0000000010006657 R15: ffff8880b8728340 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555761f5c8 CR3: 000000000e734000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_write arch/x86/include/asm/apic.h:405 [inline] lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:415 clockevents_program_event+0x1c1/0x350 kernel/time/clockevents.c:334 hrtimer_interrupt+0x54a/0x990 kernel/time/hrtimer.c:1830 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1026 [inline] __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1043 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline] sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1037 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 ae f2 2d f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 73 98 92 f5 65 8b 05 c4 32 33 74 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc90000a18e40 EFLAGS: 00000206 RAX: 6bd3f81f22f86f00 RBX: 1ffff920001431cc RCX: ffffffff8170ce6a RDX: dffffc0000000000 RSI: ffffffff8c0acac0 RDI: 0000000000000001 RBP: ffffc90000a18ed0 R08: ffffffff942cc91f R09: 1ffffffff2859923 R10: dffffc0000000000 R11: fffffbfff2859924 R12: dffffc0000000000 R13: 1ffff920001431c8 R14: ffffc90000a18e60 R15: 0000000000000246 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 spin_unlock_bh include/linux/spinlock.h:396 [inline] __batadv_dat_purge net/batman-adv/distributed-arp-table.c:186 [inline] batadv_dat_purge+0x2de/0x3c0 net/batman-adv/distributed-arp-table.c:205 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 rescuer_thread+0x63f/0x10a0 kernel/workqueue.c:3487 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244