rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state()
authorZqiang <qiang1.zhang@intel.com>
Thu, 13 Oct 2022 04:41:48 +0000 (12:41 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 31 Dec 2022 12:32:56 +0000 (13:32 +0100)
commit80a3e7ab477b3655615fc1627c88c248d4ad28d9
tree60a77408b7ee4a30d1f5880c1c0b9b6d84503d1d
parent1373e1b7206de7464b266475def8925afc54cdd5
rcu: Fix __this_cpu_read() lockdep warning in rcu_force_quiescent_state()

[ Upstream commit ceb1c8c9b8aa9199da46a0f29d2d5f08d9b44c15 ]

Running rcutorture with non-zero fqs_duration module parameter in a
kernel built with CONFIG_PREEMPTION=y results in the following splat:

BUG: using __this_cpu_read() in preemptible [00000000]
code: rcu_torture_fqs/398
caller is __this_cpu_preempt_check+0x13/0x20
CPU: 3 PID: 398 Comm: rcu_torture_fqs Not tainted 6.0.0-rc1-yoctodev-standard+
Call Trace:
<TASK>
dump_stack_lvl+0x5b/0x86
dump_stack+0x10/0x16
check_preemption_disabled+0xe5/0xf0
__this_cpu_preempt_check+0x13/0x20
rcu_force_quiescent_state.part.0+0x1c/0x170
rcu_force_quiescent_state+0x1e/0x30
rcu_torture_fqs+0xca/0x160
? rcu_torture_boost+0x430/0x430
kthread+0x192/0x1d0
? kthread_complete_and_exit+0x30/0x30
ret_from_fork+0x22/0x30
</TASK>

The problem is that rcu_force_quiescent_state() uses __this_cpu_read()
in preemptible code instead of the proper raw_cpu_read().  This commit
therefore changes __this_cpu_read() to raw_cpu_read().

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
kernel/rcu/tree.c