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 78F404657EA; Wed, 21 Jan 2026 23:12:05 +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=1769037125; cv=none; b=nv2hf/5fCFBbiuEMOcnwlQ1shg53wQnl8qnI2Lrx2hI7rohJkwJbXPFv3jNGfvJeSt9LhY05+7kG4G8XylyVdWf60+4XuaHSMbFnhMAB664p2IUhWObmUIjCAb1akd+6tnu0liBC+E08dLYL+RomGTThmcOlT2ATP70wSa6v73U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769037125; c=relaxed/simple; bh=RsJAlnh+wqpqLqaCD87s58RXfCbOFr+W/tXIEvm9Q0U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ybx+HQQNe6lHQ+QpoZ0XpbJC2vH8MrhU4GppgDmkX/Yjh+NF2Ev+wggWLfNjk1Zqgaxh5GGxPdT9Myk9ttigDpbnpqIradvNQGgDfgj0HNYr3kS5LJx5FGYnpYjbWiC4Ea0Sli3F8Xrf1AkXEjqEn/DkLntqUYVwp2AV39u9Irs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FlATPMXx; 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="FlATPMXx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84D12C16AAE; Wed, 21 Jan 2026 23:12:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769037123; bh=RsJAlnh+wqpqLqaCD87s58RXfCbOFr+W/tXIEvm9Q0U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FlATPMXx7dM7vkoG04Q152O4i65yF8HQWyz99qakCkE4mTq8J34TgJ7XWDtxoF9BO gJoFlRB0KzEtzhC1g3fCE8obJlPGANos7wvn2/hgV0YvrxoHSnk0cjFjZf1/v2caEV ZItlaw82/Kuoqzoa9I3ZGYzS4UHVKOA4glBJCB1nfzsE7M3BNKUEB0y/SClIww59B0 55ZKL1foxzifcZCiKup9Ne/Y7PxOdmipyEOYvwr+BorejSCkcKcglGA7/RpKlT5HIK XghquMqb/2UJfiNljAoEo/B1xgzBw+zmNklw/JBbqtY1gVeyf13GGwuwrTRRYVdtFl 3lBffTXJFKbmw== From: Tejun Heo To: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev Cc: void@manifault.com, andrea.righi@linux.dev, changwoo@igalia.com, emil@etsalapatis.com, Tejun Heo Subject: [PATCH 21/34] sched_ext: When calling ops.dispatch() @prev must be on the same scx_sched Date: Wed, 21 Jan 2026 13:11:27 -1000 Message-ID: <20260121231140.832332-22-tj@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260121231140.832332-1-tj@kernel.org> References: <20260121231140.832332-1-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 682dbaa22488..d27c6394d452 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2298,9 +2298,10 @@ 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; @@ -2324,7 +2325,7 @@ 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); -- 2.52.0