rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=58fc/1/0x4000000000000000 softirq=135647/135650 fqs=24 rcu: (detected by 1, t=10502 jiffies, g=213097, q=157 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 20237 Comm: kworker/u4:20 Not tainted 6.5.0-rc7-syzkaller-00164-g382d4cd18475 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Workqueue: bat_events batadv_nc_worker RIP: 0010:__kasan_check_read+0x0/0x20 mm/kasan/shadow.c:31 Code: 41 5c 41 5d 41 5e 41 5f 5d c3 48 c7 c7 75 6d a8 8c 48 89 de eb 0a 48 c7 c7 ad 6d a8 8c 4c 89 fe e8 e5 25 d6 08 31 db eb d4 90 0f 1e fa 89 f6 48 8b 0c 24 31 d2 e9 bf ea ff ff 66 2e 0f 1f 84 RSP: 0018:ffffc900000076f8 EFLAGS: 00000003 RAX: 0000000000000001 RBX: 000000000000006b RCX: ffff88803e400000 RDX: 0000000000000014 RSI: 0000000000000008 RDI: ffffffff907b4308 RBP: ffffc900000079c8 R08: dffffc0000000000 R09: 1ffffffff20f6860 R10: dffffc0000000000 R11: fffffbfff20f6861 R12: ffff88803e400ac0 R13: 0000000000000003 R14: ffff88803e400b60 R15: ffff88803e400b60 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbbf76c66e4 CR3: 000000002ebfc000 CR4: 00000000003506f0 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 kernel/locking/lockdep.c:228 [inline] check_wait_context kernel/locking/lockdep.c:4805 [inline] __lock_acquire+0x8ab/0x7f70 kernel/locking/lockdep.c:5094 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5761 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 debug_object_activate+0x163/0x530 lib/debugobjects.c:717 debug_hrtimer_activate kernel/time/hrtimer.c:422 [inline] debug_activate kernel/time/hrtimer.c:477 [inline] enqueue_hrtimer+0x30/0x310 kernel/time/hrtimer.c:1087 __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0x6c0/0xd10 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline] __sysvec_apic_timer_interrupt+0x13f/0x480 arch/x86/kernel/apic/apic.c:1115 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x25a/0x520 kernel/locking/lockdep.c:5765 Code: 2b 00 74 08 4c 89 f7 e8 74 89 79 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:ffffc900158cf9a0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92002b19f40 RCX: ffffffff816b26e5 RDX: 0000000000000000 RSI: ffffffff8b0aa9e0 RDI: ffffffff8b58af60 RBP: ffffc900158cfaf0 R08: dffffc0000000000 R09: 1ffffffff20f687b R10: dffffc0000000000 R11: fffffbfff20f687c R12: 1ffff92002b19f3c R13: dffffc0000000000 R14: ffffc900158cfa00 R15: 0000000000000246 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] batadv_nc_purge_paths+0xe8/0x3a0 net/batman-adv/network-coding.c:442 batadv_nc_worker+0x2d3/0x5c0 net/batman-adv/network-coding.c:720 process_one_work+0x92c/0x12c0 kernel/workqueue.c:2600 worker_thread+0xa63/0x1210 kernel/workqueue.c:2751 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: rcu_preempt kthread starved for 10454 jiffies! g213097 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:26384 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 schedule+0xc3/0x180 kernel/sched/core.c:6786 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1609 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1808 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 5116 Comm: kworker/1:6 Not tainted 6.5.0-rc7-syzkaller-00164-g382d4cd18475 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Workqueue: events fqdir_free_fn RIP: 0010:csd_lock_wait kernel/smp.c:296 [inline] RIP: 0010:smp_call_function_single+0x45f/0x1510 kernel/smp.c:630 Code: 07 4f 0b 00 41 83 e4 01 75 16 e8 4c 4b 0b 00 4d 89 fc 44 8b 7c 24 2c eb 46 e8 3d 4b 0b 00 eb 3f 4d 89 fc 44 8b 7c 24 2c f3 90 <42> 0f b6 04 2b 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 1a 4b 0b RSP: 0018:ffffc9000515f9e0 EFLAGS: 00000293 RAX: ffffffff81806d16 RBX: 1ffff92000a2bf55 RCX: ffff88807b270000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000515fb50 R08: ffffffff81806cd9 R09: 1ffffffff1d30f45 R10: dffffc0000000000 R11: fffffbfff1d30f46 R12: 1ffff92000a2bf50 R13: dffffc0000000000 R14: ffffc9000515faa8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff5ca395390 CR3: 0000000034421000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_barrier+0x32e/0x540 kernel/rcu/tree.c:4049 fqdir_free_fn+0x32/0x130 net/ipv4/inet_fragment.c:164 process_one_work+0x92c/0x12c0 kernel/workqueue.c:2600 worker_thread+0xa63/0x1210 kernel/workqueue.c:2751 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x2e/0x60 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304