From nobody Sun Oct 5 16:29:41 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 29C4C26CE3A for ; Fri, 1 Aug 2025 14:17:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754057877; cv=none; b=QIb18JcYctzBMiM6DWDq8XZXdaGkTmmmrq5gC089VtdZsMaYMErvcWcjqsz6klZzniA0B7yAzpP5jP3tNxpEv0pN1SrDJpvhIF+hHRZAnArbalIShkofNPCjgkq2keMH+sMiz85t+WUKSGEVW0/mgsUxmOwhzgKsf7HAsSrV8fs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754057877; c=relaxed/simple; bh=2sYU4jHFbjyd1yjtFmZkOj2kjSLSWAglphbzQJ89pv4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=bbkHBigLRJbXcBZqwpIDh2MYTLgJG8q23xAeJPBc2Ey0Ob8pXIEMO/eCxm3lxISCDQUYGb1Ytl5cOi6bIV48xG2i9g4s3BI04tZuf4QfxUbWqh+7LtyI5gl/VXLAJawMdzYMrae2Ow7fxH0WXvKagZgsNcpjQkkYfTIrEasCMwo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5186716A3; Fri, 1 Aug 2025 07:17:47 -0700 (PDT) Received: from e127648.cambridge.arm.com (e127648.arm.com [10.1.27.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 627073F673; Fri, 1 Aug 2025 07:17:53 -0700 (PDT) From: Christian Loehle To: christian.loehle@arm.com, linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev, tj@kernel.org, void@manifault.com, arighi@nvidia.com Cc: mingo@redhat.com, peterz@infradead.org Subject: [PATCH 1/3] sched_ext: Mark scx_bpf_cpu_rq as NULL returnable Date: Fri, 1 Aug 2025 15:17:39 +0100 Message-Id: <20250801141741.355059-2-christian.loehle@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250801141741.355059-1-christian.loehle@arm.com> References: <20250801141741.355059-1-christian.loehle@arm.com> 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" scx_bpf_cpu_rq() obviously returns NULL on invalid cpu. Mark it as such. While kf_cpu_valid() will trigger scx_ops_error() that leads to the BPF scheduler exiting, this isn't guaranteed to be immediate, allowing for a dereference of a NULL scx_bpf_cpu_rq() return value. Cc: stable@vger.kernel.org Fixes: 6203ef73fa5c ("sched/ext: Add BPF function to fetch rq") Signed-off-by: Christian Loehle Acked-by: Andrea Righi --- kernel/sched/ext.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 7dd5cbcb7a06..b734f55f3318 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -7599,7 +7599,7 @@ BTF_ID_FLAGS(func, scx_bpf_get_online_cpumask, KF_ACQ= UIRE) BTF_ID_FLAGS(func, scx_bpf_put_cpumask, KF_RELEASE) BTF_ID_FLAGS(func, scx_bpf_task_running, KF_RCU) BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU) -BTF_ID_FLAGS(func, scx_bpf_cpu_rq) +BTF_ID_FLAGS(func, scx_bpf_cpu_rq, KF_RET_NULL) #ifdef CONFIG_CGROUP_SCHED BTF_ID_FLAGS(func, scx_bpf_task_cgroup, KF_RCU | KF_ACQUIRE) #endif --=20 2.34.1