From a33ad03aaed2c39d29a27a64ee55ff919810de59 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 18 Mar 2025 10:23:36 +0100 Subject: [PATCH] rcu/nocb: Dump gp state even if rdp gp itself is not offloaded When a stall is detected, the state of each NOCB CPU is dumped along with the state of each NOCB group. The latter part however is incidentally ignored if the NOCB group leader happens not to be offloaded itself. Fix this to make sure related precious informations aren't lost over a stall report. Reported-by: "Paul E. McKenney" Signed-off-by: Frederic Weisbecker Reviewed-by: "Paul E. McKenney" Signed-off-by: Neeraj Upadhyay (AMD) --- kernel/rcu/tree_nocb.h | 3 +++ kernel/rcu/tree_stall.h | 3 +-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index b473ff056f493..cb29b6bb0ed40 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -1564,6 +1564,9 @@ static void show_rcu_nocb_state(struct rcu_data *rdp) if (rdp->nocb_gp_rdp == rdp) show_rcu_nocb_gp_state(rdp); + if (!rcu_segcblist_is_offloaded(&rdp->cblist)) + return; + nocb_next_rdp = list_next_or_null_rcu(&rdp->nocb_gp_rdp->nocb_head_rdp, &rdp->nocb_entry_rdp, typeof(*rdp), diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 486c00536207d..4fa64c9590838 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -953,8 +953,7 @@ void show_rcu_gp_kthreads(void) for_each_possible_cpu(cpu) { rdp = per_cpu_ptr(&rcu_data, cpu); cbs += data_race(READ_ONCE(rdp->n_cbs_invoked)); - if (rcu_segcblist_is_offloaded(&rdp->cblist)) - show_rcu_nocb_state(rdp); + show_rcu_nocb_state(rdp); } pr_info("RCU callbacks invoked since boot: %lu\n", cbs); show_rcu_tasks_gp_kthreads(); -- 2.47.2