From mboxrd@z Thu Jan 1 00:00:00 1970 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 2356B2DF714; Sat, 20 Sep 2025 01:00:11 +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=1758330011; cv=none; b=DmQ3VMsK2giyFQgaCG99HHNdeN2Ga7wWSkb6k7f8DWnA4wPACsqMU+VUpVJveIfFQKO88HP4GPmlMeO5oelOqjAWts2PeSdPufjzokm4neGZ6CHEMNV3YAnlTB073GDwCFXqLEHqy/N6kudJdC7/YEVhzYYmtO9To15Nwm3AKU4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758330011; c=relaxed/simple; bh=1h7JbbWJxult9FJRkXv1UbPtXhywndlgT7Un/HQmmHs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oKfyTMwkSHp51tX5FzMfSm9d8tzcE+hkj7QPFarSGdfahM9EtQO/HimpwcuFdW4orsdDxE909oOB6Sbw54zOHjH3c6AjZJYw40GkSf/s/iOQenjA4elOK75WHvTPogRtP7AnEdqD6cSaHWlHALK2L7EGvkiRPMLPXx6Rysci7AU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rHDkIf7b; 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="rHDkIf7b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDBAAC4CEF0; Sat, 20 Sep 2025 01:00:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758330011; bh=1h7JbbWJxult9FJRkXv1UbPtXhywndlgT7Un/HQmmHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rHDkIf7b/2PQbKWdpIoxyBeQ1g6s1voGXdqiRjAtC4YNVW1Jg/+O5AbRL4V14yXPl GuW297mjNSTvDhd43AFVXRXlhTMt2FY8sJ+T/ioXzx/6sndNeSwy9dvVvAVo+MUr/v XYZub0/o5NlDjSHCZc0qGb//h1E6FxXU7qsy/Kpn01BLPqOr1QlkPhIfcIvQJ45tHu kI9FyQ9TeLI8DdZKfPMm28LZNm8YahJ2AKY8vRVQukQ46KIRJK3Yo+SDgTO7Yhoafn cgOo/QKHp0GSHYo5oaf3FiW7Ct0DY4Fjxi5bwG6BTiYhKqbHXBleYd+bv6EuSgCsN8 hePPCGj5fBEaQ== From: Tejun Heo To: void@manifault.com, arighi@nvidia.com, multics69@gmail.com Cc: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev, memxor@gmail.com, bpf@vger.kernel.org, Tejun Heo Subject: [PATCH 34/46] sched_ext: When calling ops.dispatch() @prev must be on the same scx_sched Date: Fri, 19 Sep 2025 14:58:57 -1000 Message-ID: <20250920005931.2753828-35-tj@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250920005931.2753828-1-tj@kernel.org> References: <20250920005931.2753828-1-tj@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: 8bit The @prev parameter passed into ops.dispatch() is expected to be on the same sched. Passing in @prev which isn't on the sched can spuriously trigger failures that can kill the scheduler. Pass in @prev iff it's on the same sched. Signed-off-by: Tejun Heo --- kernel/sched/ext.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index efe01ba84e2d..714b45a55112 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2182,8 +2182,9 @@ static bool scx_dispatch_sched(struct scx_sched *sch, struct rq *rq, struct task_struct *prev) { struct scx_dsp_ctx *dspc = this_cpu_ptr(scx_dsp_ctx); - bool prev_on_scx = prev->sched_class == &ext_sched_class; int nr_loops = SCX_DSP_MAX_LOOPS; + bool prev_on_sch = (prev->sched_class == &ext_sched_class) && + sch == rcu_access_pointer(prev->scx.sched); if (consume_global_dsq(sch, rq)) return true; @@ -2205,7 +2206,7 @@ static bool scx_dispatch_sched(struct scx_sched *sch, struct rq *rq, dspc->nr_tasks = 0; SCX_CALL_OP(sch, SCX_KF_DISPATCH, dispatch, rq, - cpu_of(rq), prev_on_scx ? prev : NULL); + cpu_of(rq), prev_on_sch ? prev : NULL); flush_dispatch_buf(sch, rq); -- 2.51.0