syzbot

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 <f3> 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:
 <NMI>
 </NMI>
 <IRQ>
 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
 </IRQ>
 <TASK>
 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 <bf> 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>
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:
 <TASK>
 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>
task:syz.0.3464      state:R  running task     stack:28608 pid:20905 tgid:20902 ppid:5814   flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>
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:
 <TASK>
 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
 </TASK>
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 <fa> 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:
 <IRQ>
 </IRQ>
 <TASK>
 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
 </TASK>