linux-kernel - [PATCH sched_ext/for-6.19] sched_ext: Mark racy bitfields to prevent adding fields that can't tolerate races

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <5d2305143c29ed781438acc9b92fb781@kernel.org>
Date: Wed, 05 Nov 2025 12:03:08 -1000
From: Tejun Heo <tj@...nel.org>
To: David Vernet <void@...ifault.com>, Andrea Righi <arighi@...dia.com>, Changwoo Min <changwoo@...lia.com>
Cc: sched-ext@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH sched_ext/for-6.19] sched_ext: Mark racy bitfields to prevent adding fields that can't tolerate races

The warned bitfields in struct scx_sched are updated racily from concurrent
CPUs causing RMW races, which is fine for these boolean warning flags. Add a
comment marking this area to prevent future fields that can't tolerate racy
updates from being added here.

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 kernel/sched/ext_internal.h |    4 ++++
 1 file changed, 4 insertions(+)

--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -895,6 +895,10 @@ struct scx_sched {
 	struct scx_dispatch_q	**global_dsqs;
 	struct scx_sched_pcpu __percpu *pcpu;

+	/*
+	 * Updates to the following warned bitfields can race causing RMW issues
+	 * but it doesn't really matter.
+	 */
 	bool			warned_zero_slice:1;
 	bool			warned_deprecated_rq:1;