rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1176/1:b..l (detected by 0, t=10502 jiffies, g=24257, q=31) task:kworker/u4:6 state:R running task stack:23544 pid: 1176 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 preempt_schedule_notrace+0x5b/0xd0 kernel/sched/core.c:6538 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:36 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline] trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x458/0x510 kernel/locking/lockdep.c:5596 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:687 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:410 [inline] batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:721 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 10485 jiffies! g24257 f0x0 RCU_GP_DOING_FQS(6) ->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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6687 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:643 RIP: 0010:force_qs_rnp+0x2/0x760 kernel/rcu/tree.c:2614 Code: 07 e8 72 50 5b 00 e9 95 fc ff ff e8 b8 50 5b 00 e9 56 fc ff ff 48 8b 3c 24 e8 5a 50 5b 00 e9 0e fc ff ff 0f 1f 44 00 00 41 57 <41> 56 41 55 41 54 55 53 48 83 ec 58 0f b6 05 70 d2 35 0a c6 05 69 RSP: 0018:ffffc90000d37d78 EFLAGS: 00000202 RAX: 00000000ffffda41 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000006 RDI: ffffffff8162ede0 RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff817d01d8 R11: 0000000000000001 R12: fffffbfff16c1e30 R13: ffffc90000d37dc8 R14: 0000000000000001 R15: 0000000000000000 rcu_gp_fqs kernel/rcu/tree.c:1913 [inline] rcu_gp_fqs_loop+0x394/0x800 kernel/rcu/tree.c:1971 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 11838 Comm: syz-executor.4 Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2599 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5593 Code: c7 a5 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 7c 24 08 00 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:ffffc90004577338 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920008aee69 RCX: e9dea97a144a6d3b RDX: 1ffff110035bd863 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8fcff9e7 R10: fffffbfff1f9ff3c R11: 0000000000086089 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8b981ae0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:267 [inline] rcu_read_lock include/linux/rcupdate.h:687 [inline] is_bpf_text_address+0x36/0x170 kernel/bpf/core.c:706 kernel_text_address kernel/extable.c:151 [inline] kernel_text_address+0xbd/0xf0 kernel/extable.c:120 __kernel_text_address+0x9/0x30 kernel/extable.c:105 unwind_get_return_address arch/x86/kernel/unwind_orc.c:318 [inline] unwind_get_return_address+0x51/0x90 arch/x86/kernel/unwind_orc.c:313 arch_stack_walk+0x93/0xe0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:121 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1700 [inline] slab_free_freelist_hook+0x81/0x190 mm/slub.c:1725 slab_free mm/slub.c:3483 [inline] kfree+0xe4/0x530 mm/slub.c:4543 tty_free_file drivers/tty/tty_io.c:220 [inline] tty_open+0x7e0/0x1000 drivers/tty/tty_io.c:2149 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4c8/0x11d0 fs/open.c:822 do_open fs/namei.c:3428 [inline] path_openat+0x1c9a/0x2740 fs/namei.c:3561 do_filp_open+0x1aa/0x400 fs/namei.c:3588 do_sys_openat2+0x16d/0x4d0 fs/open.c:1200 do_sys_open fs/open.c:1216 [inline] __do_sys_openat fs/open.c:1232 [inline] __se_sys_openat fs/open.c:1227 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1227 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f4a59723a39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4a56c99188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f4a59826f60 RCX: 00007f4a59723a39 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f4a5977dc5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc1afa8f5f R14: 00007f4a56c99300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e8 72 50 5b 00 callq 0x5b5077 5: e9 95 fc ff ff jmpq 0xfffffc9f a: e8 b8 50 5b 00 callq 0x5b50c7 f: e9 56 fc ff ff jmpq 0xfffffc6a 14: 48 8b 3c 24 mov (%rsp),%rdi 18: e8 5a 50 5b 00 callq 0x5b5077 1d: e9 0e fc ff ff jmpq 0xfffffc30 22: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 27: 41 57 push %r15 * 29: 41 56 push %r14 <-- trapping instruction 2b: 41 55 push %r13 2d: 41 54 push %r12 2f: 55 push %rbp 30: 53 push %rbx 31: 48 83 ec 58 sub $0x58,%rsp 35: 0f b6 05 70 d2 35 0a movzbl 0xa35d270(%rip),%eax # 0xa35d2ac 3c: c6 .byte 0xc6 3d: 05 .byte 0x5 3e: 69 .byte 0x69