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authorPaul E. McKenney <paulmck@kernel.org>2020-08-05 10:35:16 -0700
committerPaul E. McKenney <paulmck@kernel.org>2020-08-24 18:37:54 -0700
commit4569c5ee95d5695bfd794ae968c2d59b3e69129a (patch)
tree0fd4a226e4570a6d60085b0d665faec3b8c82474 /kernel/rcu
parentc0f97f20e5d97a1358ade650fcf6a322c0c9bc72 (diff)
rcu/nocb: Add a warning for non-GP kthread running GP code
This commit increases RCU's ability to defend itself by emitting a warning if one of the nocb CB kthreads invokes the GP kthread's wait function. This warning augments a similar check that is carried out at the end of rcutorture testing and when RCU CPU stall warnings are emitted. The problem with those checks is that the miscreants have long since departed and disposed of any and all evidence. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree_plugin.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 4d63ee3de7a9..cb1e8c8befb9 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1926,6 +1926,7 @@ static void nocb_gp_wait(struct rcu_data *my_rdp)
* nearest grace period (if any) to wait for next. The CB kthreads
* and the global grace-period kthread are awakened if needed.
*/
+ WARN_ON_ONCE(my_rdp->nocb_gp_rdp != my_rdp);
for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_cb_rdp) {
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Check"));
rcu_nocb_lock_irqsave(rdp, flags);