rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4693/1:b..l (detected by 1, t=10503 jiffies, g=13645, q=701) task:syz-executor state:R running task stack:20784 pid: 4693 ppid: 4689 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 vprintk_emit+0x149/0x150 kernel/printk/printk.c:2275 _printk+0xda/0x130 kernel/printk/printk.c:2299 batadv_check_known_mac_addr+0x272/0x3b0 net/batman-adv/hard-interface.c:522 batadv_hard_if_event+0x4a0/0x17e0 net/batman-adv/hard-interface.c:986 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] dev_set_mac_address+0x2e8/0x400 net/core/dev.c:9140 dev_set_mac_address_user+0x2d/0x50 net/core/dev.c:9154 do_setlink+0x8b0/0x3d60 net/core/rtnetlink.c:2739 __rtnl_newlink net/core/rtnetlink.c:3455 [inline] rtnl_newlink+0x1658/0x1a50 net/core/rtnetlink.c:3577 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5687 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x46d/0x620 net/socket.c:2072 __do_sys_sendto net/socket.c:2084 [inline] __se_sys_sendto net/socket.c:2080 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2080 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8e6c0ca1ce RSP: 002b:00007ffe0d969df8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055557fc74500 RCX: 00007f8e6c0ca1ce RDX: 000000000000002c RSI: 00007f8e6ce06670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffe0d969e74 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f8e6ce06670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10547 jiffies! g13645 f0x0 RCU_GP_WAIT_FQS(5) ->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:28016 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3550 Comm: klogd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:match_held_lock+0x77/0xb0 kernel/locking/lockdep.c:5102 Code: 00 48 c7 c1 80 cf b5 8f 48 29 c8 48 c1 f8 06 48 be ab aa aa aa aa aa aa aa 48 0f af f0 b9 01 00 00 00 48 39 d6 74 02 31 c9 5b <89> c8 c3 e8 21 0b 24 fa 85 c0 74 f1 83 3d 8e 54 cd 03 00 75 e8 48 RSP: 0018:ffffc900010df840 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88807e25d940 RCX: 0000000000000000 RDX: 0000000000000010 RSI: ffff8880b903a358 RDI: ffff88807e25e430 RBP: 00000000ffffffff R08: ffffffff8f0ea008 R09: ffffffff8f0ea018 R10: ffffffff8f0ea010 R11: ffffffff8f0ea003 R12: 0000000000000000 R13: 0000000000000046 R14: ffff8880b903a358 R15: ffff88807e25e430 FS: 00007f1b8491ec80(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1a246d400 CR3: 000000007d9bf000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5366 [inline] lock_is_held_type+0xa6/0x190 kernel/locking/lockdep.c:5666 lock_is_held include/linux/lockdep.h:287 [inline] lockdep_assert_rq_held kernel/sched/sched.h:1317 [inline] ttwu_do_activate+0x9a/0x370 kernel/sched/core.c:3618 ttwu_queue kernel/sched/core.c:3842 [inline] try_to_wake_up+0x618/0x1050 kernel/sched/core.c:4165 autoremove_wake_function+0x13/0xf0 kernel/sched/wait.c:416 __wake_up_common+0x2a4/0x4e0 kernel/sched/wait.c:108 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up_sync_key+0x11a/0x190 kernel/sched/wait.c:205 sock_def_readable+0x136/0x250 net/core/sock.c:3101 unix_dgram_sendmsg+0x1201/0x18a0 net/unix/af_unix.c:1946 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x46d/0x620 net/socket.c:2072 __do_sys_sendto net/socket.c:2084 [inline] __se_sys_sendto net/socket.c:2080 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2080 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1b84a6e407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffff67a64c0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1b8491ec80 RCX: 00007f1b84a6e407 RDX: 0000000000000049 RSI: 00007ffff67a6600 RDI: 0000000000000003 RBP: 00007ffff67a6a30 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffff67a6a48 R13: 00007ffff67a6600 R14: 000000000000002e R15: 00007ffff67a6600