rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=65ec/1/0x4000000000000000 softirq=44455/44455 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5206/1:b..l P3564/1:b..l rcu: (detected by 0, t=10502 jiffies, g=38213, q=208 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9783 Comm: syz.5.943 Not tainted 6.16.0-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x0/0x90 kernel/kcov.c:320 Code: 7c 11 10 48 89 74 11 18 48 89 44 11 20 e9 98 38 a9 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 90 9c 92 65 8b 15 78 65 RSP: 0018:ffffc90000a08c68 EFLAGS: 00000002 RAX: ffffffff8986566d RBX: 1861b67f54000000 RCX: ffff88805c6c1e00 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000010 RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014117c R12: dffffc0000000000 R13: ffff88805b2ad8c8 R14: ffff88805b2ad800 R15: 0000000000000001 FS: 00007f9a942576c0(0000) GS:ffff888125d57000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f867eb86358 CR3: 000000003109c000 CR4: 00000000003526f0 Call Trace: advance_sched+0x51a/0xc90 net/sched/sch_taprio.c:961 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:124 [inline] RIP: 0010:lock_release+0x78/0x3e0 kernel/locking/lockdep.c:5884 Code: 0d f6 05 7a 53 ec 0d 01 0f 84 ad 02 00 00 83 3d 5d 9a 02 0e 00 0f 84 44 02 00 00 65 8b 05 60 85 fe 10 85 c0 0f 85 35 02 00 00 <65> 4c 8b 3c 25 08 90 9c 92 41 83 bf ec 0a 00 00 00 0f 85 1e 02 00 RSP: 0018:ffffc9000bd06f90 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff90b57601 RCX: e3a0fc48db294100 RDX: ffffc9000bd07101 RSI: ffffffff8be1ba20 RDI: ffffffff8be1b9e0 RBP: dffffc0000000000 R08: ffffc9000bd074f0 R09: 0000000000000000 R10: ffffc9000bd07118 R11: fffff520017a0e25 R12: ffffc9000bd07500 R13: ffffffff8172aae5 R14: ffffffff8e13f0e0 R15: ffffffff8172aae5 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 skb_clone+0x212/0x3a0 net/core/skbuff.c:2050 __netlink_deliver_tap_skb net/netlink/af_netlink.c:300 [inline] __netlink_deliver_tap+0x404/0x850 net/netlink/af_netlink.c:325 netlink_deliver_tap+0x19c/0x1b0 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1262 [inline] netlink_sendskb+0x68/0x140 net/netlink/af_netlink.c:1271 nlmsg_unicast include/net/netlink.h:1184 [inline] genlmsg_unicast include/net/genetlink.h:553 [inline] genlmsg_reply include/net/genetlink.h:563 [inline] ctrl_getfamily+0x499/0x590 net/netlink/genetlink.c:1473 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:727 __sys_sendto+0x3bd/0x520 net/socket.c:2180 __do_sys_sendto net/socket.c:2187 [inline] __se_sys_sendto net/socket.c:2183 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2183 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9a933909fc Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b RSP: 002b:00007f9a94255ec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f9a94255fc0 RCX: 00007f9a933909fc RDX: 0000000000000020 RSI: 00007f9a94256010 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00007f9a94255f14 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004 R13: 00007f9a94255f68 R14: 00007f9a94256010 R15: 0000000000000000 task:kworker/u8:7 state:R running task stack:23016 pid:3564 tgid:3564 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217 Code: 08 90 9c 92 65 8b 15 58 6a dc 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 <83> fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c RSP: 0018:ffffc9000c6b7a18 EFLAGS: 00000246 RAX: ffffffff8b3456d1 RBX: 0000000000000001 RCX: ffff888031795a00 RDX: 0000000000000000 RSI: ffffffff8be1ba20 RDI: ffffffff8be1b9e0 RBP: fffffffffffffe38 R08: 0000000000000000 R09: ffffffff8b345592 R10: dffffc0000000000 R11: ffffffff8b3454c0 R12: dffffc0000000000 R13: ffffffff8b345592 R14: ffff88807c864d80 R15: 0000000000000224 rcu_read_unlock include/linux/rcupdate.h:869 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x211/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:udevd state:R running task stack:22952 pid:5206 tgid:5206 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x1323/0x2390 arch/x86/kernel/unwind_orc.c:494 Code: 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 <49> 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 e9 7b ef ff ff RSP: 0018:ffffc900030b7438 EFLAGS: 00000206 RAX: ffffffff81697f8f RBX: ffffffff8fb3bc48 RCX: ffffffff8fb3bc48 RDX: ffffffff8fb3bc40 RSI: ffffffff902ef20c RDI: ffffffff8be1b9e0 RBP: ffffffff8fb3bc40 R08: 0000000000000007 R09: ffffffff8172aae5 R10: ffffc900030b75b8 R11: fffff52000616eb9 R12: ffffffff81697f33 R13: ffffffff8fb3bc40 R14: ffffc900030b7568 R15: ffffffff8fb3bc44 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 alloc_empty_file+0x55/0x1d0 fs/file_table.c:234 path_openat+0x107/0x3830 fs/namei.c:4041 do_filp_open+0x1fa/0x410 fs/namei.c:4082 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6b1b115c3a RSP: 002b:00007ffc01d971e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055a3fdca1da0 RCX: 00007f6b1b115c3a RDX: 0000000000090800 RSI: 000055a3fdc27160 RDI: 00000000ffffff9c RBP: 000055a3fdc27160 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 000055a3fdc307c0 R13: 00000000000000ff R14: 000055a3dbf95be0 R15: 00007ffc01d97470 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g38213 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=30960 rcu: rcu_preempt kthread starved for 10502 jiffies! g38213 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16aa/0x4c90 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245