From patchwork Tue Jul 9 19:57:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 13728477 X-Patchwork-Delegate: bhelgaas@google.com Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 41B0014F108 for ; Tue, 9 Jul 2024 20:27:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720556850; cv=none; b=VbA/a8EAHlgNs71xboI9rTxN2YkwD+tu0s/sOpU7OMxVDfGpvAxf7XoU7nQJVDVqr2qJg+PFC+6fzV2TXIHLZp0ucW52G/23Qbrf4eOdIjQ9S42VPU9IyE8LgIqs7UyhJVYS/jlM7LsJHKMgHWBy53NC1PiQ4W6/WQOAzwkKEQU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720556850; c=relaxed/simple; bh=Grz+iCnGALIJgOkups8vD/xhHYut8O5IgcRUVEl2CYU=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=WndTQkCIqUCB4fQDZopWX4CCi78qxAGu+Jr8W1uC8SfINU/+YyU0Fpesvkj+biDChSs2WMM0Nz4kF9akc5DaJqn0dt/d6bEjhVYa4AerMAGSFUosLIpQNLdLQPPxkQTn38HjcxH3wZ9Qocup12eR6gT656bMoAXwwW6p4jg35Y8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=OREnGqB/; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="OREnGqB/" Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 469K8dFh027144 for ; Tue, 9 Jul 2024 13:27:28 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=from :to:cc:subject:date:message-id:mime-version :content-transfer-encoding:content-type; s=s2048-2021-q4; bh=Hyy KRsdN7VvUv7WDUfO7bx06ZGoHXYrPnn/wh26pnvA=; b=OREnGqB/KxJjb9WA8s+ qL3saYbx8OHVeSWL7YIcpaRjuMNUMKxt5dSjfm/MtszfHBlXH3a+t9x9JlzJuHyu x0l4lUT8393Pry+AwiY0Mhfnc0pRn4Ekj5FabGYWhOOEeHMgXF5NnzcGOCAMt0Ov KBbv5P+ObZfMxQnK4mYM+sMuF92lPeSdDjJpcjJDzjsRqhxmPVLXhuY1rTgXQSRM 673JBN4q+YWYsEDRfVNAFnZ/TBAjzLLTMGeFlut9xLKl6Tjvn2uBHuNSRyvv2Qun dTWy5VuwQ5icmJWBIyebKkIjLNUlcTZxFfJ5nEvMIiwkbn0odViWU1jiPYq1+Aht PuQ== Received: from mail.thefacebook.com ([163.114.134.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 408um5e354-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 09 Jul 2024 13:27:28 -0700 (PDT) Received: from twshared15999.02.ash9.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c08b:78::c78f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1544.11; Tue, 9 Jul 2024 19:57:26 +0000 Received: by devbig638.nha1.facebook.com (Postfix, from userid 544533) id 895E11060AB77; Tue, 9 Jul 2024 12:57:17 -0700 (PDT) From: Keith Busch To: CC: , , Keith Busch , Dan Williams Subject: [RESEND PATCH] PCI: fix recursive device locking Date: Tue, 9 Jul 2024 12:57:16 -0700 Message-ID: <20240709195716.3354637-1-kbusch@meta.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: EbV79jULbhzfX2Q9z2LblG9CFpJOjkxh X-Proofpoint-ORIG-GUID: EbV79jULbhzfX2Q9z2LblG9CFpJOjkxh X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-07-09_09,2024-07-09_01,2024-05-17_01 From: Keith Busch If one of the bus' devices has subordinates, the recursive call locks itself, so no need to lock the device before the recursion or it will surely deadlock. Fixes: dbc5b5c0d268f87 ("PCI: Add missing bridge lock to pci_bus_lock()" Reviewed-by: Dan Williams Signed-off-by: Keith Busch --- Sending to the correct mailing list this time, and fixed up two typos in the commit message. drivers/pci/pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index df550953fa260..5ab13bf5a3caa 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5488,9 +5488,10 @@ static void pci_bus_lock(struct pci_bus *bus) pci_dev_lock(bus->self); list_for_each_entry(dev, &bus->devices, bus_list) { - pci_dev_lock(dev); if (dev->subordinate) pci_bus_lock(dev->subordinate); + else + pci_dev_lock(dev); } } @@ -5502,7 +5503,8 @@ static void pci_bus_unlock(struct pci_bus *bus) list_for_each_entry(dev, &bus->devices, bus_list) { if (dev->subordinate) pci_bus_unlock(dev->subordinate); - pci_dev_unlock(dev); + else + pci_dev_unlock(dev); } pci_dev_unlock(bus->self); }