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 EBDED30FF36; Wed, 25 Feb 2026 05:01:32 +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=1771995693; cv=none; b=BK9ye06fg3Zaw1LjLLA0vYFBjuOToR7boeT/YXvEKshckIZrL92Ci1LgL2ZDwdStejA1NJjt5eoMuRWOIsL9dBY6nl6MUhLquRXA3ag033nLza67cViEwewIKXOMD/Cl/1Rq39BcLf2f2gZATrJAKwXgyXtqmTKJ/Bbr7ssMGpI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771995693; c=relaxed/simple; bh=3/mKhjAXqvZ0FAsZItI7vRYMA/HK0yR/LO3DfP+GPhc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sz6d5s3vKHt82I1LtuGowN9wKA37zuDokwOY/GRHvjHberu3tugWyHhrqXzEY57d567g1f+ON5vLqTsTlWeFOBFlXEYqKAIlYo9xtg1RQeMcunqy25GxToBHFFk5sMltiZ/oXRrsm3D89S42ZvqUB/Tq2/Wb5qJNLhD8DzPjM+A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jD7KBozF; 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="jD7KBozF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88235C116D0; Wed, 25 Feb 2026 05:01:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771995692; bh=3/mKhjAXqvZ0FAsZItI7vRYMA/HK0yR/LO3DfP+GPhc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jD7KBozF39orCPeQSV8q7oy+0jMu2YbdKTzDPVhWCRtu6bme+ak5oG9npuGTDH3X1 R4l50jThfmAJgAZbl8RjesuggpKHYpZUPBmUJl0xoI7/8/x3cwsLZc+5SeIx2/r979 7xk8NWeUt6gH065EYsmprXPUHgtqB7OWObp4ulVnAHuGyZFUYU8Psu5lwzxCwTl/Yk 48JJUYLO9+ZiCEOtjYYbLrr2oHijo/50OWCu148r7Pwvz94gg6UxsiKr5coxXQLOtL eNQn3StJwzPDjzn5y0Dat/P0B7eRepecj9imaerQweSG+VEhVokyKmNd8ud0EdoyEq w60CLdN27iuSg== From: Tejun Heo To: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev Cc: void@manifault.com, arighi@nvidia.com, changwoo@igalia.com, emil@etsalapatis.com, hannes@cmpxchg.org, mkoutny@suse.com, cgroups@vger.kernel.org, Tejun Heo Subject: [PATCH 21/34] sched_ext: When calling ops.dispatch() @prev must be on the same scx_sched Date: Tue, 24 Feb 2026 19:00:56 -1000 Message-ID: <20260225050109.1070059-22-tj@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225050109.1070059-1-tj@kernel.org> References: <20260225050109.1070059-1-tj@kernel.org> Precedence: bulk X-Mailing-List: cgroups@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 99ef2a1cc3ac..ed1491df0829 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2388,9 +2388,10 @@ 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; s32 cpu = cpu_of(rq); + 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; @@ -2414,7 +2415,7 @@ 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, - prev_on_scx ? prev : NULL); + prev_on_sch ? prev : NULL); flush_dispatch_buf(sch, rq); -- 2.53.0