syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11836/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=44497, q=4012 ncpus=2)
task:syz.3.1499      state:R  running task     stack:25952 pid:11836 tgid:11836 ppid:9470   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7078
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x6c/0xb0 kernel/rcu/tree.c:737
Code: 80 00 48 c7 c3 d8 7c 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 22 8b 03 65 ff 0d a1 c6 7e 7e 74 10 83 e0 04 <c1> e8 02 5b 41 5e 41 5f e9 92 31 6b 0a e8 52 38 85 ff eb e9 89 d9
RSP: 0018:ffffc900049b7ba0 EFLAGS: 00000202
RAX: 0000000000000004 RBX: ffff8880b8737cd8 RCX: ffffffff817aaf04
RDX: 0000000000000000 RSI: ffffffff8c5fafc0 RDI: ffffffff8c5faf80
RBP: ffffc900049b7d08 R08: ffffffff90197e77 R09: 1ffffffff2032fce
R10: dffffc0000000000 R11: fffffbfff2032fcf R12: 1ffff92000936f80
R13: dffffc0000000000 R14: ffffffff8e2e5b58 R15: dffffc0000000000
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xe3/0x550 kernel/locking/lockdep.c:5820
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1161 [inline]
 sched_mm_cid_remote_clear_old kernel/sched/core.c:10497 [inline]
 task_mm_cid_work+0x3a0/0x790 kernel/sched/core.c:10557
 task_work_run+0x251/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3be4185d29
RSP: 002b:00007ffe9906af08 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 00007ffe9906b030 RCX: 00007f3be4185d29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3be4375fac
RBP: 00007f3be4375fac R08: 7fffffffffffffff R09: 00007ffe9906b1ff
R10: 00007ffe9906b010 R11: 0000000000000246 R12: 00000000000ab331
R13: 00007ffe9906b010 R14: 0000000000000226 R15: 00000000000ab10b
 </TASK>