From nobody Wed Apr 1 09:07:42 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 2499B346AD7; Tue, 31 Mar 2026 22:18:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774995526; cv=none; b=RlnuqnyJ2GJBTcSFdnkiTRmXrIRdASoB4nhAB9joxovC6HyRrpzogoUkfO6JvIotAJ5QdEwem24p0ckLlc3wscm2lWck0ei9TOlorOMT6j67sdgsXGPYebBbtfPAjHEwB+H0gDWH8SkMPZLG0/DazGS+hCyc5XYHCl8pkslW0TY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774995526; c=relaxed/simple; bh=wUdaIIELWJl+i7uH46Ifi81pzzNyIffVW8w36LxytFw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=D4MHjfXv1Dz5MRusVQ+5TKkZrDk1FK3iVf8+bSkTQTN9mLuR8Yd5XFqVQoLpaQnWA2e6LNjRkvV+pZcTE+Bnu2cEEn5rZYztv7AwCyo/Wysl5YkI/6QKLMekBoRBlVDndnXuty1hrDOYWw7LqKiGNHGazT6cEBv40j9gPvPt3l0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=esdDgrvC; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="esdDgrvC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1774995525; x=1806531525; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=wUdaIIELWJl+i7uH46Ifi81pzzNyIffVW8w36LxytFw=; b=esdDgrvCmxvga0NPVS0jm53qJelONBCjpCSjoRI9b6pywYs84qGgXmo+ 3JVt6aqTSArztaZr64bpk6SEDfGNK54pQTnbmSFFj/4RuvwC637Ql3zXW yLjlDYoufuptKoGXh3brDvMW/7vBZjtzmonH0/zfPPBzYT4fmEllQYn07 rLLY/WcKSsDGQzdVPkU7xdPBFo70jsGrThoXa/un3t3VO2jXivG/mE9sx dV0gCx4jqgR68DTF6VQ8ckS80beDqTYejKF+TS7SlaF5w4GJQK1HpbluH Xs5Sqb8PLQ6UmuWqFwL2lVSj2LOB9A6bD4QLMAvL/g8bB66yjVpE0R4BB Q==; X-CSE-ConnectionGUID: lMH+abpSRUCBRLgEixH7Ug== X-CSE-MsgGUID: 4DRMpt7XTTCOLNYD6V8oRA== X-IronPort-AV: E=McAfee;i="6800,10657,11745"; a="87416319" X-IronPort-AV: E=Sophos;i="6.23,152,1770624000"; d="scan'208";a="87416319" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Mar 2026 15:18:44 -0700 X-CSE-ConnectionGUID: auU7s6NqTF+xcTm0JNyBkA== X-CSE-MsgGUID: thBuCzoaRAiTE/lR+URFNQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,152,1770624000"; d="scan'208";a="225668430" Received: from gsse-cloud1.jf.intel.com ([10.54.39.91]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Mar 2026 15:18:45 -0700 From: Matthew Brost To: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Carlos Santa , Ryan Neph , stable@vger.kernel.org, Tejun Heo , Lai Jiangshan , Waiman Long Subject: [PATCH] workqueue: Add pool_workqueue to pending_pwqs list when unplugging multiple inactive works Date: Tue, 31 Mar 2026 15:18:39 -0700 Message-Id: <20260331221839.1033423-1-matthew.brost@intel.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable In unplug_oldest_pwq(), the first inactive pool_workqueue is activated correctly. However, if multiple inactive works exist on the same pool_workqueue, subsequent works fail to activate because wq_node_nr_active.pending_pwqs is empty =E2=80=94 the list insertion is ski= pped when the pool_workqueue is plugged. Fix this by checking for additional inactive works in unplug_oldest_pwq() and updating wq_node_nr_active.pending_pwqs accordingly. Cc: Carlos Santa Cc: Ryan Neph Cc: stable@vger.kernel.org Cc: Tejun Heo Cc: Lai Jiangshan Cc: Waiman Long Cc: linux-kernel@vger.kernel.org Fixes: 4c065dbce1e8 ("workqueue: Enable unbound cpumask update on ordered w= orkqueues") Signed-off-by: Matthew Brost --- This bug was first reported by Google, where the Xe driver appeared to hang due to a fencing signal not completing. We traced the issue to work items not being scheduled, and it can be trivially reproduced on drm-tip with the following commands: shell0: for i in {1..100}; do echo "Run $i"; xe_exec_threads --r \ threads-rebind-bindexecqueue; done shell1: for i in {1..1000}; do echo "toggle $i"; echo f > \ /sys/devices/virtual/workqueue/cpumask; echo ff > \ /sys/devices/virtual/workqueue/cpumask; echo fff > \ /sys/devices/virtual/workqueue/cpumask ; echo ffff > \ /sys/devices/virtual/workqueue/cpumask; sleep .1; done --- kernel/workqueue.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b77119d71641..b2cdb44ccb56 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1849,8 +1849,20 @@ static void unplug_oldest_pwq(struct workqueue_struc= t *wq) raw_spin_lock_irq(&pwq->pool->lock); if (pwq->plugged) { pwq->plugged =3D false; - if (pwq_activate_first_inactive(pwq, true)) + if (pwq_activate_first_inactive(pwq, true)) { + if (!list_empty(&pwq->inactive_works)) { + struct worker_pool *pool =3D pwq->pool; + struct wq_node_nr_active *nna =3D + wq_node_nr_active(wq, pool->node); + + raw_spin_lock(&nna->lock); + if (list_empty(&pwq->pending_node)) + list_add_tail(&pwq->pending_node, + &nna->pending_pwqs); + raw_spin_unlock(&nna->lock); + } kick_pool(pwq->pool); + } } raw_spin_unlock_irq(&pwq->pool->lock); } --=20 2.34.1