rcu: Mark accesses to rcu_state.n_force_qs

stable inclusion
from stable-v5.10.88
commit 70692b06208c09c3cc2a0de2aaef63f4f139970a
bugzilla: 186058 https://gitee.com/openeuler/kernel/issues/I4QW6A

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=70692b06208c09c3cc2a0de2aaef63f4f139970a



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commit 2431774f upstream.

This commit marks accesses to the rcu_state.n_force_qs.  These data
races are hard to make happen, but syzkaller was equal to the task.

Reported-by:  <syzbot+e08a83a1940ec3846cd5@syzkaller.appspotmail.com>
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>