From nobody Tue Feb 10 06:04:26 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2870C7EE22 for ; Thu, 11 May 2023 21:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239411AbjEKVmO (ORCPT ); Thu, 11 May 2023 17:42:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238958AbjEKVmL (ORCPT ); Thu, 11 May 2023 17:42:11 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E25315BA6 for ; Thu, 11 May 2023 14:41:49 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id 98e67ed59e1d1-24df8644eaeso4907388a91.1 for ; Thu, 11 May 2023 14:41:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683841308; x=1686433308; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=43muZZqhwTl5Zf6bR8xbpoiNJBmmJ6GoS2BIrk8XQg0=; b=4MsedK4JufBOK2Pya7wQCIDxG0sCQ1VFTXWDgZhatiOWtPY8opQlb3hL15OT5+unZG c92gYZtsjWyA0xBBYuP1vjtV9F4vB2xfCoB1TbwZDS6rC9lEcLm8vQnbtah9R9tQVvk8 3XqKLnL9WIFnp4raTswUlTUXryUFeRB5X3s/tRMH4GmJMbvmyj/r3b8iejmBq+6Dz+Bu BpteMnQmPKMuyMxqdEMLiL+po2QzBiS1Jne4oUn4GHrbhRN5fi04GbTI4PMxSqwaTflW htw1CwW32Ld/0Udqzx2i3OH+tBT7Cvm3ak2yGnWGLZ4oRNFpkr2Mv5GY3T2/7v1h5+uU 4Pwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683841308; x=1686433308; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=43muZZqhwTl5Zf6bR8xbpoiNJBmmJ6GoS2BIrk8XQg0=; b=c1OYRs8RKrmS/GFh12BfcbgHoB76lNpsfFKDKBIIoBFCubCOLvzcLClqFYO1E3ihzt g6xUcg7ZArghCFavVUMPbEjk0iY1vEV6YpKRYqY+HRYB1+vBqy41U2RtwW+VVTM3lekG fqpQNNPetcMmpVteCuuSVLBDIfSwggn4NnfE2W6T72/GVvnIC9ENdYMIg+EXjoMhx466 KR5QRsocooFxYxewBa20/3VxwLgS6MyKro9NOXQ6kETf/nogrgkXQ0aB3ptTzlIDmJiD 8Xmn76aBxxYxhhadAqJKnncTAcK0zwwxJWNJha3aRz4UU7Bp5j5md9UHOeuJ3pgf94dU k8DA== X-Gm-Message-State: AC+VfDzHTCXmwiYxf7ssDExztS717hZbclkINtdyKE7qNX7JGSvXS+ZT xtY2ZIjdPIS19XQ95rpVtFydSVQoQFM+q5tx1qcWUFERhLrTEHprYP2RNbJ0/f39nWoCLq77rDX 0VqixBtElE4gFKYtk9v16tgYEgDss57iItH+7dg6TARXk8zuqiFZuin15sKfCUHt+qYhcRtM= X-Google-Smtp-Source: ACHHUZ4s/bA5bbWMEoCZHDspkz2P/SKgGc9ShoCkPP2udc8klgmNRKyV+96ayDFCh+GNSU2whHAGdftp/1LC X-Received: from jstultz-noogler2.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:600]) (user=jstultz job=sendgmr) by 2002:a17:90a:f517:b0:250:43bb:dced with SMTP id cs23-20020a17090af51700b0025043bbdcedmr6155590pjb.5.1683841308026; Thu, 11 May 2023 14:41:48 -0700 (PDT) Date: Thu, 11 May 2023 21:41:30 +0000 In-Reply-To: <20230406194053.876844-1-arve@android.com> Mime-Version: 1.0 References: <20230406194053.876844-1-arve@android.com> X-Mailer: git-send-email 2.40.1.606.ga4b1b128d6-goog Message-ID: <20230511214144.1924757-1-jstultz@google.com> Subject: [PATCH] sched/wait: Fix a kthread_park race with wait_woken() From: John Stultz To: LKML Cc: "=?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?=" , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , John Stultz Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Arve Hj=C3=B8nnev=C3=A5g kthread_park and wait_woken have a similar race that kthread_stop and wait_woken used to have before it was fixed in cb6538e740d7543cd989128625cf8cac4b471e0a. Extend that fix to also cover kthread_park. Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Daniel Bristot de Oliveira Cc: Valentin Schneider Signed-off-by: Arve Hj=C3=B8nnev=C3=A5g Signed-off-by: John Stultz --- This seemingly slipped by, so I wanted to resend it for review. --- kernel/sched/wait.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 133b74730738..a9cf49da884b 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -425,9 +425,9 @@ int autoremove_wake_function(struct wait_queue_entry *w= q_entry, unsigned mode, i } EXPORT_SYMBOL(autoremove_wake_function); =20 -static inline bool is_kthread_should_stop(void) +static inline bool is_kthread_should_stop_or_park(void) { - return (current->flags & PF_KTHREAD) && kthread_should_stop(); + return (current->flags & PF_KTHREAD) && (kthread_should_stop() || kthread= _should_park()); } =20 /* @@ -459,7 +459,7 @@ long wait_woken(struct wait_queue_entry *wq_entry, unsi= gned mode, long timeout) * or woken_wake_function() sees our store to current->state. */ set_current_state(mode); /* A */ - if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop()) + if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop_or_park= ()) timeout =3D schedule_timeout(timeout); __set_current_state(TASK_RUNNING); =20 --=20 2.40.1.606.ga4b1b128d6-goog