rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P154/1:b..l P3546/1:b..l (detected by 0, t=10502 jiffies, g=6745, q=296) task:udevd state:R running task stack:23168 pid: 3546 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6552 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6577 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x121/0x1c0 kernel/sched/wait.c:205 sock_def_readable+0x135/0x240 net/core/sock.c:3095 __netlink_sendskb net/netlink/af_netlink.c:1258 [inline] netlink_sendskb+0x96/0x130 net/netlink/af_netlink.c:1264 netlink_unicast+0x3a6/0x990 net/netlink/af_netlink.c:1352 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1905 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2436 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg+0x19a/0x260 net/socket.c:2526 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f9271e14a4b RSP: 002b:00007ffdd797f718 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000555b5d5129e0 RCX: 00007f9271e14a4b RDX: 0000000000000000 RSI: 00007ffdd797f728 RDI: 0000000000000004 RBP: 0000555b5d531400 R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000000a5 R14: 0000000000000000 R15: 0000000000000000 task:kworker/u4:2 state:R running task stack:23000 pid: 154 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:kasan_check_range+0x1ac/0x290 mm/kasan/generic.c:189 Code: 4c 89 d5 48 8d 5d 07 48 85 ed 48 0f 49 dd 48 83 e3 f8 48 29 dd 74 12 41 80 39 00 0f 85 a2 00 00 00 49 ff c1 48 ff cd 75 ee 5b <41> 5e 41 5f 5d c3 45 84 f6 75 61 41 f7 c6 00 ff 00 00 75 5d 41 f7 RSP: 0018:ffffc90001ff7a60 EFLAGS: 00000256 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8162e2bc RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e0aa6e8 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1c154de R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920003fef58 R13: dffffc0000000000 R14: fffffbfff1c154de R15: ffff88801c540c80 instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] cpumask_test_cpu include/linux/cpumask.h:344 [inline] cpu_online include/linux/cpumask.h:895 [inline] trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0xcc/0x4f0 kernel/locking/lockdep.c:5594 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0xc1/0x5b0 net/batman-adv/network-coding.c:723 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 10555 jiffies! g6745 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:26752 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3837 Comm: dhcpcd Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lock_acquire+0x89/0x4f0 kernel/locking/lockdep.c:5591 Code: 8c 48 c7 44 24 50 f0 e1 62 81 4c 8d 64 24 40 49 c1 ec 03 48 b8 f1 f1 f1 f1 00 f2 f2 f2 4b 89 04 2c 43 c7 44 2c 09 f2 f2 f2 00 <43> c7 44 2c 11 f3 f3 f3 f3 66 43 c7 44 2c 15 f3 f3 43 c6 44 2c 17 RSP: 0018:ffffc9000359f200 EFLAGS: 00000806 RAX: f2f2f200f1f1f1f1 RBX: ffff8880b8f3dfc0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880b8f3dfc0 RBP: ffffc9000359f360 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920006b3e48 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007ff856d33740(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7f7f624ca0 CR3: 0000000025c95000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: local_lock_acquire+0x1d/0x70 include/linux/local_lock_internal.h:29 put_cpu_partial+0x6b/0x1a0 mm/slub.c:2556 do_slab_free mm/slub.c:3487 [inline] ___cache_free+0xe3/0x100 mm/slub.c:3506 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283 ____kasan_kmalloc+0x2f/0xf0 mm/kasan/common.c:479 kasan_kmalloc include/linux/kasan.h:264 [inline] __kmalloc_node_track_caller+0x195/0x390 mm/slub.c:4963 kmalloc_reserve net/core/skbuff.c:356 [inline] __alloc_skb+0x12c/0x590 net/core/skbuff.c:427 alloc_skb include/linux/skbuff.h:1162 [inline] alloc_skb_with_frags+0xa3/0x780 net/core/skbuff.c:6170 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2533 unix_dgram_sendmsg+0x702/0x2090 net/unix/af_unix.c:1798 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] sock_write_iter+0x39b/0x530 net/socket.c:1079 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ff856dfdbf2 Code: 89 c7 48 89 44 24 08 e8 7b 34 fa ff 48 8b 44 24 08 48 83 c4 28 c3 c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 6f 48 8b 15 07 a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffca3534d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055b5153a9b60 RCX: 00007ff856dfdbf2 RDX: 0000000000000046 RSI: 00007ffca3534d80 RDI: 0000000000000005 RBP: 00007ffca3534d80 R08: 0000000000000008 R09: 0000000000000035 R10: 0000000000000000 R11: 0000000000000246 R12: 000055b4e53f9efc R13: 00007ffca35351b0 R14: 000055b5154aab40 R15: 0000000000000001