From 7c405fb3279b39244b260b54f1bd6488689ae235 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Wed, 18 Mar 2026 17:56:21 -0700 Subject: rcu: Use an intermediate irq_work to start process_srcu() Since commit c27cea4416a3 ("rcu: Re-implement RCU Tasks Trace in terms of SRCU-fast") we switched to SRCU in BPF. However as BPF instrument can happen basically everywhere (including where a scheduler lock is held), call_srcu() now needs to avoid acquiring scheduler lock because otherwise it could cause deadlock [1]. Fix this by following what the previous RCU Tasks Trace did: using an irq_work to delay the queuing of the work to start process_srcu(). [boqun: Apply Joel's feedback] [boqun: Apply Andrea's test feedback] Reported-by: Andrea Righi Closes: https://lore.kernel.org/all/abjzvz_tL_siV17s@gpd4/ Fixes: commit c27cea4416a3 ("rcu: Re-implement RCU Tasks Trace in terms of SRCU-fast") Link: https://lore.kernel.org/rcu/3c4c5a29-24ea-492d-aeee-e0d9605b4183@nvidia.com/ [1] Suggested-by: Zqiang Tested-by: Andrea Righi Tested-by: Paul E. McKenney Tested-by: Joel Fernandes Signed-off-by: Boqun Feng --- include/linux/srcutree.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index dfb31d11ff05..be76fa4fc170 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -95,6 +95,7 @@ struct srcu_usage { unsigned long reschedule_jiffies; unsigned long reschedule_count; struct delayed_work work; + struct irq_work irq_work; struct srcu_struct *srcu_ssp; }; -- cgit v1.2.3