syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4492/1:b..l
	(detected by 1, t=10502 jiffies, g=35981, q=30)
task:kworker/u4:12   state:R  running task     stack:25520 pid: 4492 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc9000305faa0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3136e32dd6da5a00
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f980
RBP: ffffc9000305fbc0 R08: dffffc0000000000 R09: 1ffffffff203a818
R10: dffffc0000000000 R11: fffffbfff203a819 R12: ffffffff8c31eaa0
R13: 1ffff9200060bf60 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline]
 batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10520 jiffies! g35981 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:27728 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>
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: 9580 Comm: syz.6.1121 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:212 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:156 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:263 [inline]
RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:208
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 8f 5d d0 02 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc90003647a48 EFLAGS: 00000046
RAX: 00000000000004de RBX: 00000000000004de RCX: 0000000000000838
RDX: 0000000000000000 RSI: 00000000000004de RDI: 0000000000000838
RBP: 0000000000000001 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d
R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: dffffc0000000000
R13: 0000000010005a98 R14: ffffffff8be319d8 R15: dffffc0000000000
FS:  0000555570de5500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1eef5fb000 CR3: 0000000068c68000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 apic_write arch/x86/include/asm/apic.h:395 [inline]
 lapic_next_event+0x5b/0x70 arch/x86/kernel/apic/apic.c:468
 clockevents_program_event+0x1bc/0x310 kernel/time/clockevents.c:334
 hrtimer_start_range_ns+0xa9a/0xc20 kernel/time/hrtimer.c:1287
 posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329
 dequeue_signal+0x174/0x440 kernel/signal.c:696
 get_signal+0x6fe/0x12c0 kernel/signal.c:2781
 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f413de5fdd0
Code: d5 00 49 39 54 24 28 0f 82 5e 03 00 00 40 0f b6 fe c6 44 24 0e 01 45 31 ed 45 31 f6 89 7c 24 08 85 c0 0f 84 10 01 00 00 66 90 <48> 8b 3c 24 49 8b 54 24 40 4c 89 f0 4a 03 14 ef 80 3d c1 6f 3a 00
RSP: 002b:00007ffd1a627460 EFLAGS: 00000287
RAX: 0000000000000001 RBX: ffffffff81d6187b RCX: ffffffff81d6187b
RDX: 000000000000187b RSI: ffffffff81d6187b RDI: 0000000000000012
RBP: 0000000000000000 R08: 00007f413e1ef000 R09: 00007f413e1f1000
R10: 0000000081d6187f R11: 0000000000000012 R12: 00007f413e205038
R13: 000000000000094f R14: ffffffff81d6186d R15: 00007f413ed34720
 </TASK>