rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=b6dc/1/0x4000000000000000 softirq=57407/57408 fqs=6 rcu: (detected by 1, t=10502 jiffies, g=97277, q=1013 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5280 Comm: kworker/u4:9 Not tainted 6.7.0-rc1-syzkaller-00268-gac40916a3f72 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Workqueue: bat_events batadv_tt_purge RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:134 [inline] RIP: 0010:lock_release+0x3a3/0x690 kernel/locking/lockdep.c:5776 Code: 20 bc cc 8a e8 0e ec 17 09 b8 ff ff ff ff 65 0f c1 05 e9 75 9a 7e 83 f8 01 0f 85 c8 01 00 00 9c 58 f6 c4 02 0f 85 b3 01 00 00 <48> f7 04 24 00 02 00 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df 48 RSP: 0018:ffffc90000007c40 EFLAGS: 00000046 RAX: 0000000000000046 RBX: 49da982df18c1733 RCX: ffffc90000007c90 RDX: 1ffff110049d250e RSI: ffffffff8accbc20 RDI: ffffffff8b2f0e40 RBP: 1ffff92000000f8a R08: 0000000000000000 R09: fffffbfff1e327e2 R10: ffffffff8f193f17 R11: 0000000000000004 R12: 0000000000000004 R13: 0000000000000005 R14: ffff888024e92878 R15: ffff888024e91dc0 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f438d0c66e4 CR3: 00000000456d9000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_objects_fill_pool lib/debugobjects.c:616 [inline] debug_object_activate+0x158/0x490 lib/debugobjects.c:713 debug_hrtimer_activate kernel/time/hrtimer.c:422 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x23/0x310 kernel/time/hrtimer.c:1087 __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0xa12/0xc20 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1065 [inline] __sysvec_apic_timer_interrupt+0x105/0x400 arch/x86/kernel/apic/apic.c:1082 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1076 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x1ef/0x520 kernel/locking/lockdep.c:5721 Code: c1 05 bd 68 9a 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc9000491fa08 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000923f43 RCX: ffffffff8167301e RDX: 0000000000000001 RSI: ffffffff8accbc20 RDI: ffffffff8b2f0e40 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff23e35eb R10: ffffffff91f1af5f R11: 0000000000000002 R12: 0000000000000001 R13: 0000000000000000 R14: ffff8880432b4dd8 R15: 0000000000000000 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] batadv_tt_local_purge+0x145/0x3c0 net/batman-adv/translation-table.c:1354 batadv_tt_purge+0x8b/0xbb0 net/batman-adv/translation-table.c:3560 process_one_work+0x886/0x15d0 kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 rcu: rcu_preempt kthread starved for 10361 jiffies! g97277 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:27616 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5376 [inline] __schedule+0xedb/0x5af0 kernel/sched/core.c:6688 __schedule_loop kernel/sched/core.c:6763 [inline] schedule+0xe9/0x270 kernel/sched/core.c:6778 schedule_timeout+0x137/0x290 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xb10 kernel/rcu/tree.c:1631 rcu_gp_kthread+0x24b/0x380 kernel/rcu/tree.c:1830 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 5161 Comm: kworker/1:4 Not tainted 6.7.0-rc1-syzkaller-00268-gac40916a3f72 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Workqueue: events fqdir_free_fn RIP: 0010:write_comp_data+0x7e/0x80 kernel/kcov.c:262 Code: 00 00 4a 8d 34 dd 28 00 00 00 48 39 f2 72 1b 48 83 c7 01 48 89 38 4c 89 44 30 e0 4c 89 4c 30 e8 4c 89 54 30 f0 4a 89 4c d8 20 90 f3 0f 1e fa 48 8b 0c 24 40 0f b6 d6 40 0f b6 f7 31 ff e9 69 RSP: 0018:ffffc9000466fb18 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff817bf4d3 RDX: ffff88801aaf3b80 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffffc9000466fc30 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000003 R12: 1ffff920008cdf68 R13: 0000000000000000 R14: 0000000000000001 R15: ffff8880b983d600 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200044c0 CR3: 000000001e8b2000 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_single+0x203/0x650 kernel/smp.c:650 rcu_barrier+0x284/0x6c0 kernel/rcu/tree.c:4082 fqdir_free_fn+0x32/0x160 net/ipv4/inet_fragment.c:164 process_one_work+0x886/0x15d0 kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242