Commit-ID: c8020a67e625c714c4dbedc8ae2944b461e204ec
Gitweb: http://git.kernel.org/tip/c8020a67e625c714c4dbedc8ae2944b461e204ec
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 10 Aug 2012 16:55:59 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 23 Sep 2012 07:42:51 -0700
rcu: Protect rcu_node accesses during CPU stall warnings
The print_other_cpu_stall() function accesses a number of rcu_node
fields without protection from the ->lock. In theory, this is not
a problem because the fields accessed are all integers, but in
practice the compiler can get nasty. Therefore, the commit extends
the existing critical section to cover the entire loop body.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcutree.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 2c4ee4c..2cf8eb3 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -746,14 +746,15 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave(&rnp->lock, flags);
ndetected += rcu_print_task_stall(rnp);
+ if (rnp->qsmask != 0) {
+ for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
+ if (rnp->qsmask & (1UL << cpu)) {
+ print_cpu_stall_info(rsp,
+ rnp->grplo + cpu);
+ ndetected++;
+ }
+ }
raw_spin_unlock_irqrestore(&rnp->lock, flags);
- if (rnp->qsmask == 0)
- continue;
- for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
- if (rnp->qsmask & (1UL << cpu)) {
- print_cpu_stall_info(rsp, rnp->grplo + cpu);
- ndetected++;
- }
}
/*
--
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