From nobody Tue Oct 7 15:01:30 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2DF2A2C08AC; Wed, 9 Jul 2025 10:47:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752058021; cv=none; b=GcO2DP6hc7Aktouj9Xgr20NAu3L6bWqEXM6NhCU11wPKI1wJtAsh57gs+CntlW5UTJEkbzAHOdG5Ji73ht14uFQpzp9SfV1J1Z7e76ceQ9/W+n4zO8kCz8Z0FOi+Y0IaiQWhrU4ubGBvB0gBNKiZ3qpg30aAbGoc5Z+OOC23fdU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752058021; c=relaxed/simple; bh=5COjt3uAJjZ1DcFXHjY8wDD+SZYLGK6GkQYggnCf478=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=IqvEPk3Hbhz0AyVNAb0U8kFn6XfQcFqRvPfmHGUltI4ROhFuuJYFhQfRPYSyK1P+eGQbOxGkn6bzTTxcXvdwzYW3xG+CI9x6ZX/79heKhW7SXi9DaUXVbu6OWPJMUXAOrjcO0xsYlNDIuiFvH6pblEQPaU+WgN78maD4hMxCFcg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tlwO7hhf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tlwO7hhf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FB62C4CEEF; Wed, 9 Jul 2025 10:46:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752058020; bh=5COjt3uAJjZ1DcFXHjY8wDD+SZYLGK6GkQYggnCf478=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tlwO7hhfXaV1EpMX3AXeLkAZEWLYwCbM2Xo+cgo0D5oY+NsTuNSgp8/dCkncjJAxf gosxNuDaxscnUB2uDw2Nhot5VX5kWfd/XcGNRaa7ERYzKSzSL8LKYeepdSu1rFZh6V SNpmdBBaqcorpaGGaPtdvym6ly6HO92sRVoSQhgH5Iy6yHAxAUWJUccodeBYk2ayqt sIEMxTlqoJbEMEx9RN7Sv8O5CyG2n4M/1BipyoE1ndfBedcIbYTU0UkUSASvGdXqMC 8riXaXokyaqDac+uDWazM6lh+cIfN2EAibwzEY40Edx7qNOUd1WAfnePkk0fDMD+BK +htVeXzPZil4g== From: neeraj.upadhyay@kernel.org To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, paulmck@kernel.org, joelagnelf@nvidia.com, frederic@kernel.org, boqun.feng@gmail.com, urezki@gmail.com, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang1211@gmail.com, neeraj.iitr10@gmail.com, neeraj.upadhyay@amd.com, "Neeraj Upadhyay (AMD)" Subject: [PATCH rcu 1/2] rcu/nocb: Dump gp state even if rdp gp itself is not offloaded Date: Wed, 9 Jul 2025 16:16:40 +0530 Message-Id: <20250709104641.15699-2-neeraj.upadhyay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20250709104641.15699-1-neeraj.upadhyay@kernel.org> References: <20250709104641.15699-1-neeraj.upadhyay@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Frederic Weisbecker 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 b473ff056f49..cb29b6bb0ed4 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 =3D=3D rdp) show_rcu_nocb_gp_state(rdp); =20 + if (!rcu_segcblist_is_offloaded(&rdp->cblist)) + return; + nocb_next_rdp =3D 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 486c00536207..4fa64c959083 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 =3D per_cpu_ptr(&rcu_data, cpu); cbs +=3D 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(); --=20 2.40.1