This is a note to let you know that I've just added the patch titled
rcuscale: Provide clear error when async specified without primitives
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
rcuscale-provide-clear-error-when-async-specified-wi.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 849a058043439420ed04025cc10d93ef0e282417
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
Date: Thu Aug 1 17:43:03 2024 -0700
rcuscale: Provide clear error when async specified without primitives
[ Upstream commit 11377947b5861fa59bf77c827e1dd7c081842cc9 ]
Currently, if the rcuscale module's async module parameter is specified
for RCU implementations that do not have async primitives such as RCU
Tasks Rude (which now lacks a call_rcu_tasks_rude() function), there
will be a series of splats due to calls to a NULL pointer. This commit
therefore warns of this situation, but switches to non-async testing.
Signed-off-by: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index a83cb29d37607..f90955dc15327 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -428,7 +428,7 @@ rcu_scale_writer(void *arg)
udelay(writer_holdoff);
wdp = &wdpp[i];
*wdp = ktime_get_mono_fast_ns();
- if (gp_async) {
+ if (gp_async && !WARN_ON_ONCE(!cur_ops->async)) {
retry:
if (!rhp)
rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
@@ -484,7 +484,7 @@ rcu_scale_writer(void *arg)
i++;
rcu_scale_wait_shutdown();
} while (!torture_must_stop());
- if (gp_async) {
+ if (gp_async && cur_ops->async) {
cur_ops->gp_barrier();
}
writer_n_durations[me] = i_max + 1;
