From: Paul E. McKenney Date: Wed, 24 Jun 2020 03:57:59 +0000 (-0700) Subject: rcu: Add READ_ONCE() to rcu_do_batch() access to rcu_cpu_stall_ftrace_dump X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1ef5a442a113d140580b3b8bbd6f50c9f7746397;p=linux.git rcu: Add READ_ONCE() to rcu_do_batch() access to rcu_cpu_stall_ftrace_dump Given that sysfs can change the value of rcu_cpu_stall_ftrace_dump at any time, this commit adds a READ_ONCE() to the accesses to that variable. Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index a1780a621b5e9..0fde39b8daab5 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -623,7 +623,7 @@ static void check_cpu_stall(struct rcu_data *rdp) /* We haven't checked in, so go dump stack. */ print_cpu_stall(gps); - if (rcu_cpu_stall_ftrace_dump) + if (READ_ONCE(rcu_cpu_stall_ftrace_dump)) rcu_ftrace_dump(DUMP_ALL); } else if (rcu_gp_in_progress() && @@ -632,7 +632,7 @@ static void check_cpu_stall(struct rcu_data *rdp) /* They had a few time units to dump stack, so complain. */ print_other_cpu_stall(gs2, gps); - if (rcu_cpu_stall_ftrace_dump) + if (READ_ONCE(rcu_cpu_stall_ftrace_dump)) rcu_ftrace_dump(DUMP_ALL); } }