rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16779/1:b..l P18037/1:b..l (detected by 0, t=10502 jiffies, g=89373, q=65 ncpus=2) task:syz-executor.1 state:R running task stack:26808 pid:18037 ppid:3553 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x132c/0x4330 kernel/sched/core.c:6554 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6866 irqentry_exit+0x53/0x80 kernel/entry/common.c:433 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:654 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:776 [inline] RIP: 0010:count_memcg_event_mm+0x301/0x3e0 include/linux/memcontrol.h:1094 Code: 89 fe ff ff e8 f0 1e be ff eb 1f e8 e9 1e be ff e8 44 25 b9 08 4d 85 ed 74 89 e8 da 1e be ff fb 49 bd 00 00 00 00 00 fc ff df ea 2a b9 08 89 c3 31 ff 89 c6 e8 1f 22 be ff 85 db 74 10 e8 86 RSP: 0018:ffffc9000313f560 EFLAGS: 00000287 RAX: ffffffff81cbe036 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90004262000 RSI: 00000000000140ab RDI: 00000000000140ac RBP: ffffc9000313f630 R08: ffffffff81cbdfab R09: fffffbfff209344b R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888073cca000 R13: dffffc0000000000 R14: 1ffff92000627eb0 R15: 0000000000000046 handle_mm_fault+0x158/0x5330 mm/memory.c:5224 do_user_addr_fault arch/x86/mm/fault.c:1380 [inline] handle_page_fault arch/x86/mm/fault.c:1471 [inline] exc_page_fault+0x26f/0x660 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:copy_user_enhanced_fast_string+0xa/0x40 arch/x86/lib/copy_user_64.S:166 Code: ff c9 75 f2 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 8d 0c ca 89 ca eb 20 0f 01 cb 83 fa 40 72 38 89 d1 a4 31 c0 0f 01 ca c3 89 ca eb 0a 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc9000313fa00 EFLAGS: 00050206 RAX: ffffffff84350201 RBX: 00007fffffffe000 RCX: 0000000000001000 RDX: 0000000000001000 RSI: 0000000020120000 RDI: ffff88801aa68000 RBP: ffff8880752cc610 R08: dffffc0000000000 R09: ffffed100354d200 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000001000 R13: 0000000000000000 R14: ffff88801aa68000 R15: 0000000020120000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline] _copy_from_user+0xf3/0x170 lib/usercopy.c:23 copy_from_user include/linux/uaccess.h:161 [inline] snd_rawmidi_kernel_write1+0x376/0x5f0 sound/core/rawmidi.c:1549 snd_rawmidi_write+0x5a8/0xb60 sound/core/rawmidi.c:1618 vfs_write+0x2d9/0xba0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f67be67cae9 RSP: 002b:00007f67bf4c10c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f67be79bf80 RCX: 00007f67be67cae9 RDX: 00000000fffffd2c RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00007f67be6c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f67be79bf80 R15: 00007fff01f2ed48 task:kworker/u4:4 state:R running task stack:23256 pid:16779 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x132c/0x4330 kernel/sched/core.c:6554 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6866 irqentry_exit+0x53/0x80 kernel/entry/common.c:433 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5673 Code: 2b 00 74 08 4c 89 f7 e8 6f a5 76 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc9000338f8e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000671f28 RCX: 1ffff92000671ec8 RDX: dffffc0000000000 RSI: ffffffff8aebf420 RDI: ffffffff8b3ceb60 RBP: ffffc9000338fa40 R08: dffffc0000000000 R09: fffffbfff2093445 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000671f24 R13: dffffc0000000000 R14: ffffc9000338f940 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:306 rcu_read_lock include/linux/rcupdate.h:747 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:755 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:826 [inline] batadv_iv_ogm_schedule+0x425/0x1000 net/batman-adv/bat_iv_ogm.c:869 batadv_iv_send_outstanding_bat_ogm_packet+0x6fa/0x800 net/batman-adv/bat_iv_ogm.c:1713 process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2292 worker_thread+0xa5f/0x1210 kernel/workqueue.c:2439 kthread+0x26e/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 rcu: rcu_preempt kthread starved for 10202 jiffies! g89373 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:25432 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x132c/0x4330 kernel/sched/core.c:6554 schedule+0xbf/0x180 kernel/sched/core.c:6630 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1661 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1860 kthread+0x26e/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.48-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline] RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:113 [inline] RIP: 0010:acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:572 Code: 1b fb f6 48 83 e3 08 0f 85 0b 01 00 00 4c 8d 74 24 20 e8 84 cb 01 f7 0f 1f 44 00 00 e8 9a 17 fb f6 0f 00 2d 03 05 b8 00 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 1b ad 51 f7 RSP: 0018:ffffffff8ce07b40 EFLAGS: 000002d3 RAX: ffffffff8a8ee776 RBX: 0000000000000000 RCX: ffffffff8cebd800 RDX: 0000000000000000 RSI: ffffffff8aebe2a0 RDI: ffffffff8b3ceb60 RBP: ffffffff8ce07bd0 R08: ffffffff8a8ee758 R09: fffffbfff19d7b01 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff19c0f68 R13: ffff888017b4a804 R14: ffffffff8ce07b60 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff16650642e CR3: 000000004806c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:709 cpuidle_enter_state+0x516/0xf80 drivers/cpuidle/cpuidle.c:239 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:356 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:236 [inline] do_idle+0x3ce/0x680 kernel/sched/idle.c:303 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:400 rest_init+0x28f/0x2b0 init/main.c:727 arch_call_rest_init+0xa/0xa init/main.c:887 start_kernel+0x496/0x53f init/main.c:1134 secondary_startup_64_no_verify+0xcf/0xdb