rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=fc74/1/0x4000000000000000 softirq=90266/90277 fqs=79 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20905/1:b..l P6152/1:b..l rcu: (detected by 0, t=10502 jiffies, g=70197, q=289 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9832 Comm: kworker/1:2H Not tainted 6.13.0-rc2-syzkaller-00333-ga0e3919a2df2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 Workqueue: events_highpri snd_vmidi_output_work RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:30 Code: c3 cc cc cc cc 48 83 c4 60 48 c7 c7 c8 5c 7c 8d 5b 5d 41 5c e9 41 76 7c ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 89 f6 31 d2 e9 1f f1 ff ff 66 66 2e 0f 1f RSP: 0018:ffffc90000a189e8 EFLAGS: 00000047 RAX: 0000000000000000 RBX: 0000000000000021 RCX: ffff88802e4b0b08 RDX: 1ffff11005c9616a RSI: 0000000000000008 RDI: ffffffff96e4ecc0 RBP: ffffc90000a18b38 R08: 0000000000000002 R09: 0000000000000000 R10: ffffffff96e4ecc7 R11: 0000000000000002 R12: ffff88802e4b0000 R13: 0000000000000200 R14: 0000000000000009 R15: 1ffff92000143146 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000203f7000 CR3: 000000005d08e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] hlock_class+0x4e/0x130 kernel/locking/lockdep.c:228 mark_lock+0xb5/0xc60 kernel/locking/lockdep.c:4727 mark_usage kernel/locking/lockdep.c:4670 [inline] __lock_acquire+0x9f1/0x3c40 kernel/locking/lockdep.c:5180 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] advance_sched+0x67f/0xc60 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1739 [inline] __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1865 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 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+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 f6 f3 4a f6 48 89 df e8 3e 73 4b f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 c5 68 3c f6 65 8b 05 96 23 d8 74 85 c0 74 16 5b RSP: 0018:ffffc90004fffbc0 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffff88802fa85930 RCX: 1ffffffff2dd7dca RDX: 0000000000000000 RSI: ffffffff8b6cd860 RDI: ffffffff8bd1d360 RBP: 0000000000000293 R08: 0000000000000001 R09: fffffbfff2dc9dbb R10: ffffffff96e4eddf R11: 0000000000000004 R12: 0000000000000293 R13: 0000000000001000 R14: 0000000000000000 R15: ffff88801b090c00 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] class_spinlock_irqsave_destructor include/linux/spinlock.h:572 [inline] snd_rawmidi_proceed+0x105/0x160 sound/core/rawmidi.c:1504 snd_vmidi_output_work+0x30e/0x390 sound/core/seq/seq_virmidi.c:146 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 task:kworker/u8:9 state:R running task stack:22480 pid:6152 tgid:6152 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7028 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:738 trace_lock_acquire+0x14e/0x1f0 include/trace/events/lock.h:24 lock_acquire+0x2f/0xb0 kernel/locking/lockdep.c:5820 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline] percpu_ref_put include/linux/percpu-refcount.h:351 [inline] blk_mq_dispatch_plug_list block/blk-mq.c:2866 [inline] blk_mq_flush_plug_list+0x6be/0x1c60 block/blk-mq.c:2913 __blk_flush_plug+0x2c5/0x4b0 block/blk-core.c:1213 blk_flush_plug include/linux/blkdev.h:1061 [inline] io_schedule_prepare kernel/sched/core.c:7650 [inline] io_schedule+0xba/0x130 kernel/sched/core.c:7680 rq_qos_wait+0x1a9/0x2e0 block/blk-rq-qos.c:280 __wbt_wait block/blk-wbt.c:594 [inline] wbt_wait+0x1b0/0x390 block/blk-wbt.c:658 __rq_qos_throttle+0x53/0xa0 block/blk-rq-qos.c:66 rq_qos_throttle block/blk-rq-qos.h:151 [inline] rq_qos_throttle block/blk-rq-qos.h:147 [inline] blk_mq_get_new_requests block/blk-mq.c:2974 [inline] blk_mq_submit_bio+0x8ea/0x24c0 block/blk-mq.c:3118 __submit_bio+0x384/0x540 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739 submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868 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+0x74f/0x1da0 fs/ext4/page-io.c:562 mpage_submit_folio+0x1c0/0x350 fs/ext4/inode.c:1932 mpage_process_page_bufs+0x46d/0x990 fs/ext4/inode.c:2045 mpage_prepare_extent_to_map+0x758/0x1470 fs/ext4/inode.c:2546 ext4_do_writepages+0x968/0x32d0 fs/ext4/inode.c:2688 ext4_writepages+0x303/0x730 fs/ext4/inode.c:2824 do_writepages+0x1b3/0x820 mm/page-writeback.c:2702 __writeback_single_inode+0x166/0xfa0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x606/0xfa0 fs/fs-writeback.c:1976 __writeback_inodes_wb+0xff/0x2e0 fs/fs-writeback.c:2047 wb_writeback+0x803/0xb80 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0x8c0/0xbc0 fs/fs-writeback.c:2343 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 task:syz.0.3464 state:R running task stack:28608 pid:20905 tgid:20902 ppid:5814 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6935 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] timerfd_clock_was_set+0x164/0x310 fs/timerfd.c:111 clock_was_set+0x67c/0x850 kernel/time/hrtimer.c:969 timekeeping_inject_offset+0x402/0x520 kernel/time/timekeeping.c:1481 do_adjtimex+0x369/0xaa0 kernel/time/timekeeping.c:2581 do_clock_adjtime kernel/time/posix-timers.c:1165 [inline] __do_sys_clock_adjtime+0x173/0x290 kernel/time/posix-timers.c:1177 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb8efb85d19 RSP: 002b:00007fb8f08da038 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007fb8efd76080 RCX: 00007fb8efb85d19 RDX: 0000000000000000 RSI: 0000000020000480 RDI: 0000000000000000 RBP: 00007fb8efc01a20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb8efd76080 R15: 00007ffdf179f538 rcu: rcu_preempt kthread starved for 10344 jiffies! g70197 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:28160 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6848 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 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: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc2-syzkaller-00333-ga0e3919a2df2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] RIP: 0010:acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:112 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 48 8b 05 b8 85 da 74 48 8b 00 a8 08 75 0c 66 90 0f 00 2d 48 17 b4 00 fb f4 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d70 EFLAGS: 00000246 RAX: 0000000000004000 RBX: 0000000000000001 RCX: ffffffff8b293679 RDX: 0000000000000001 RSI: ffff888021af0800 RDI: ffff888021af0864 RBP: ffff888021af0864 R08: 0000000000000001 R09: ffffed10170c6fed R10: ffff8880b8637f6b R11: 0000000000000000 R12: ffff88801eb47000 R13: ffffffff8ee14ea0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8f08dad58 CR3: 0000000065eac000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000c DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: acpi_idle_enter+0xc5/0x160 drivers/acpi/processor_idle.c:699 cpuidle_enter_state+0xaa/0x4f0 drivers/cpuidle/cpuidle.c:268 cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:389 cpuidle_idle_call kernel/sched/idle.c:230 [inline] do_idle+0x310/0x3f0 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:747 start_kernel+0x3e4/0x4d0 init/main.c:1102 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488 common_startup_64+0x13e/0x148