linux-kernel - [PATCH v6 3/3] sched_ext: deprecation warn for scx_bpf_cpu

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

Message-Id: <20250902111143.2667154-4-christian.loehle@arm.com>
Date: Tue,  2 Sep 2025 12:11:43 +0100
From: Christian Loehle <christian.loehle@....com>
To: tj@...nel.org,
	arighi@...dia.com,
	void@...ifault.com
Cc: linux-kernel@...r.kernel.org,
	sched-ext@...ts.linux.dev,
	changwoo@...lia.com,
	hodgesd@...a.com,
	mingo@...hat.com,
	peterz@...radead.org,
	jake@...lion.co.uk,
	Christian Loehle <christian.loehle@....com>
Subject: [PATCH v6 3/3] sched_ext: deprecation warn for scx_bpf_cpu_rq()

scx_bpf_cpu_rq() works on an unlocked rq which generally isn't safe.
For the common use-cases scx_bpf_cpu_rq_locked() and
scx_bpf_remote_curr() work, so add a deprecation warning
to scx_bpf_cpu_rq() so it can eventually be removed.

Signed-off-by: Christian Loehle <christian.loehle@....com>
---
 kernel/sched/ext.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index dc141144bfd6..987c7dc38545 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -7427,6 +7427,9 @@ __bpf_kfunc struct rq *scx_bpf_cpu_rq(s32 cpu)
 	if (!kf_cpu_valid(cpu, NULL))
 		return NULL;
 
+	pr_warn_once("%s() is deprecated; use scx_bpf_cpu_rq_locked() when holding rq lock "
+		     "or scx_bpf_remote_curr() to read remote curr safely.\n", __func__);
+
 	return cpu_rq(cpu);
 }
 
-- 
2.34.1