From 6a6821675d1733d7a8622570d0a69d9598a6a9e8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 1 Aug 2024 17:43:03 -0700 Subject: [PATCH] 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" Signed-off-by: Neeraj Upadhyay Signed-off-by: Sasha Levin --- kernel/rcu/rcuscale.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index 3b9783eda..cfe861bac 100755 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -398,7 +398,7 @@ 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); @@ -454,7 +454,7 @@ retry: 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;