rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=7a84/1/0x4000000000000000 softirq=21415/21416 fqs=8 rcu: (detected by 1, t=10502 jiffies, g=36297, q=202 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9431 Comm: syz-executor.2 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] RIP: 0010:lock_release+0x391/0x6a0 kernel/locking/lockdep.c:5776 Code: 85 4d 02 00 00 0b 05 ce 14 fd 12 0f 84 65 01 00 00 48 c7 c7 40 ba 0c 8b e8 bc 18 67 09 b8 ff ff ff ff 65 0f c1 05 57 45 97 7e <83> f8 01 0f 85 d3 01 00 00 9c 58 f6 c4 02 0f 85 be 01 00 00 48 f7 RSP: 0018:ffffc90000007ca8 EFLAGS: 00000057 RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffc90000007cf8 RDX: 1ffff11003e34519 RSI: ffffffff8b0cba40 RDI: ffffffff8b6e88a0 RBP: 1ffff92000000f97 R08: 0000000000000000 R09: fffffbfff1f3cdf2 R10: ffffffff8f9e6f97 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: ffff88801f1a28d0 R15: ffff88801f1a1e00 FS: 00007f7df51ff6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7df5fa8000 CR3: 00000000a5d70000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] advance_sched+0x611/0xc60 net/sched/sch_taprio.c:981 __run_hrtimer kernel/time/hrtimer.c:1692 [inline] __hrtimer_run_queues+0x20c/0xc20 kernel/time/hrtimer.c:1756 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1818 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x10f/0x410 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200 Code: be b0 01 00 00 e8 a0 ff ff ff 31 c0 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 65 48 8b 15 04 db 76 7e 65 8b 05 05 db 76 7e a9 00 01 RSP: 0018:ffffc90004c9f808 EFLAGS: 00000206 RAX: 0000000000000002 RBX: ffffc90004c9f890 RCX: ffffffff813c9cc2 RDX: ffff88801f1a1e00 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff90d89b64 R13: ffffffff90d89b69 R14: 0000000000000003 R15: ffffc90004c9f8c5 unwind_next_frame+0x600/0x23a0 arch/x86/kernel/unwind_orc.c:508 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:240 [inline] __kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2106 [inline] slab_free mm/slub.c:4280 [inline] kfree+0x129/0x370 mm/slub.c:4390 v9fs_mount+0x9d8/0xcd0 fs/9p/vfs_super.c:193 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8f/0x380 fs/super.c:1779 do_new_mount fs/namespace.c:3352 [inline] path_mount+0x14e6/0x1f20 fs/namespace.c:3679 do_mount fs/namespace.c:3692 [inline] __do_sys_mount fs/namespace.c:3898 [inline] __se_sys_mount fs/namespace.c:3875 [inline] __x64_sys_mount+0x297/0x320 fs/namespace.c:3875 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f7df5e7dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7df51ff0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f7df5fabf80 RCX: 00007f7df5e7dda9 RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 00007f7df5eca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f7df5fabf80 R15: 00007ffe7c4c4698 rcu: rcu_preempt kthread starved for 10485 jiffies! g36297 f0x0 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:28736 pid:16 tgid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0xf15/0x5c70 kernel/sched/core.c:6736 __schedule_loop kernel/sched/core.c:6813 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6828 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2572 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:1663 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:1862 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 7704 Comm: kworker/u8:10 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:write_comp_data+0x11/0x90 kernel/kcov.c:236 Code: cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 df e1 76 7e <65> 8b 05 e0 e1 76 7e a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 82 14 RSP: 0018:ffffc90003b6f908 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b94464e0 RCX: ffffffff8180f38b RDX: ffff8880a1c20000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000006 R12: ffffed1017288c9d R13: 0000000000000001 R14: ffff8880b94464e8 R15: ffff8880b953f840 FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdb997a8000 CR3: 000000000d57a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:311 [inline] smp_call_function_many_cond+0x50b/0x1590 kernel/smp.c:855 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1023 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2086 [inline] text_poke_bp_batch+0x22b/0x760 arch/x86/kernel/alternative.c:2296 text_poke_flush arch/x86/kernel/alternative.c:2487 [inline] text_poke_flush arch/x86/kernel/alternative.c:2484 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2494 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1d7/0x400 kernel/jump_label.c:829 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate mm/kfence/core.c:826 [inline] toggle_allocation_gate+0xf8/0x250 mm/kfence/core.c:818 process_one_work+0x9a9/0x1a60 kernel/workqueue.c:3254 process_scheduled_works kernel/workqueue.c:3335 [inline] worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416 kthread+0x2c1/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243