[tip: core/rcu] rcutorture: Properly set rcu_fwds for OOM handling

From: tip-bot2 for Paul E. McKenney
Date: Fri Oct 09 2020 - 02:35:26 EST


The following commit has been merged into the core/rcu branch of tip:

Commit-ID: c8fa63714763b7795a3f5fb7ed6d000763e6dccc
Gitweb: https://git.kernel.org/tip/c8fa63714763b7795a3f5fb7ed6d000763e6dccc
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate: Sun, 19 Jul 2020 14:40:31 -07:00
Committer: Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Mon, 24 Aug 2020 18:45:34 -07:00

rcutorture: Properly set rcu_fwds for OOM handling

The conversion of rcu_fwds to dynamic allocation failed to actually
allocate the required structure. This commit therefore allocates it,
frees it, and updates rcu_fwds accordingly. While in the area, it
abstracts the cleanup actions into rcu_torture_fwd_prog_cleanup().

Fixes: 5155be9994e5 ("rcutorture: Dynamically allocate rcu_fwds structure")
Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index c8206ff..7942be4 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2148,9 +2148,20 @@ static int __init rcu_torture_fwd_prog_init(void)
return -ENOMEM;
spin_lock_init(&rfp->rcu_fwd_lock);
rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
+ rcu_fwds = rfp;
return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
}

+static void rcu_torture_fwd_prog_cleanup(void)
+{
+ struct rcu_fwd *rfp;
+
+ torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
+ rfp = rcu_fwds;
+ rcu_fwds = NULL;
+ kfree(rfp);
+}
+
/* Callback function for RCU barrier testing. */
static void rcu_torture_barrier_cbf(struct rcu_head *rcu)
{
@@ -2448,7 +2459,7 @@ rcu_torture_cleanup(void)
show_rcu_gp_kthreads();
rcu_torture_read_exit_cleanup();
rcu_torture_barrier_cleanup();
- torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
+ rcu_torture_fwd_prog_cleanup();
torture_stop_kthread(rcu_torture_stall, stall_task);
torture_stop_kthread(rcu_torture_writer, writer_task);