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[2620:137:e000::1:20]) by mx.google.com with ESMTP id e19-20020a637453000000b004fb2a41a62bsi2635904pgn.656.2023.02.11.02.38.29; Sat, 11 Feb 2023 02:38:43 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=ckGbY90V; dkim=neutral (no key) header.i=@linutronix.de; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229915AbjBKKa5 (ORCPT + 99 others); Sat, 11 Feb 2023 05:30:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229658AbjBKKa4 (ORCPT ); Sat, 11 Feb 2023 05:30:56 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59B112006B; Sat, 11 Feb 2023 02:30:55 -0800 (PST) Date: Sat, 11 Feb 2023 10:30:53 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1676111453; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KxaQ+e28M8FkH0NNi2WoKjdyfNU63nRcy/3GdI0r6gE=; b=ckGbY90VZaKmE3wfqcrQhzkyijIoNGa9lT05m05BbJKTc8kkAQ0vk4z4STi1wwJ2dXTkw/ gPm8s6W6zBSMVFPzSlSU9LQYC199T2Tt/cxG+l5RexN0FGPup7mb8DUFI2R6Oeqij3h3Fs 3hTeKCb1KmYwr6tADhEfxYTivETkJsEh9MtPKnBuumEDFSrpkrAN4RoSeW23mBjuQRtrAu nlxbSdhpeuw8VunuDVECOGOaCItutjwamYHVliIcV5K/3Y3OA5LzCQ9grsXF5XWHutZccK nCeNelEA1I9Dp6N1WIBB0uLeCv/1PDXKda+rC/vrAU5cjvmadXAOnFZbq1Uv9w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1676111453; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KxaQ+e28M8FkH0NNi2WoKjdyfNU63nRcy/3GdI0r6gE=; b=zkUB6WUs314h821Etws0nGquw49t5pEFLuMxwZFgD47NHx8x9hZOlyFji19ddl0SIxG3HX MN0LSw9373zOV1Aw== From: "tip-bot2 for Pietro Borrello" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/rt: pick_next_rt_entity(): check list_entry Cc: Pietro Borrello , "Peter Zijlstra (Intel)" , Phil Auld , "Steven Rostedt (Google)" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230128-list-entry-null-check-sched-v3-1-b1a71bd1ac6b@diag.uniroma1.it> References: <20230128-list-entry-null-check-sched-v3-1-b1a71bd1ac6b@diag.uniroma1.it> MIME-Version: 1.0 Message-ID: <167611145334.4906.4760858235156037814.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757530736451725795?= X-GMAIL-MSGID: =?utf-8?q?1757530736451725795?= The following commit has been merged into the sched/core branch of tip: Commit-ID: 7c4a5b89a0b5a57a64b601775b296abf77a9fe97 Gitweb: https://git.kernel.org/tip/7c4a5b89a0b5a57a64b601775b296abf77a9fe97 Author: Pietro Borrello AuthorDate: Mon, 06 Feb 2023 22:33:54 Committer: Peter Zijlstra CommitterDate: Sat, 11 Feb 2023 11:18:10 +01:00 sched/rt: pick_next_rt_entity(): check list_entry Commit 326587b84078 ("sched: fix goto retry in pick_next_task_rt()") removed any path which could make pick_next_rt_entity() return NULL. However, BUG_ON(!rt_se) in _pick_next_task_rt() (the only caller of pick_next_rt_entity()) still checks the error condition, which can never happen, since list_entry() never returns NULL. Remove the BUG_ON check, and instead emit a warning in the only possible error condition here: the queue being empty which should never happen. Fixes: 326587b84078 ("sched: fix goto retry in pick_next_task_rt()") Signed-off-by: Pietro Borrello Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Phil Auld Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20230128-list-entry-null-check-sched-v3-1-b1a71bd1ac6b@diag.uniroma1.it --- kernel/sched/rt.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index ed2a47e..0a11f44 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1777,6 +1777,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq) BUG_ON(idx >= MAX_RT_PRIO); queue = array->queue + idx; + if (SCHED_WARN_ON(list_empty(queue))) + return NULL; next = list_entry(queue->next, struct sched_rt_entity, run_list); return next; @@ -1789,7 +1791,8 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq) do { rt_se = pick_next_rt_entity(rt_rq); - BUG_ON(!rt_se); + if (unlikely(!rt_se)) + return NULL; rt_rq = group_rt_rq(rt_se); } while (rt_rq);