From nobody Fri Dec 19 07:24:15 2025 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 769512D9EC4; Tue, 16 Dec 2025 22:14:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765923294; cv=none; b=mIosuopV+Me4oRM17LQ8sE6SgWXZhC2NdG7ht886MtgEXE+Nfyyaroq6hKB4TKCDBhL0mcrBQows1wiuCwhy77xWwLQGweQmPoZbknr3+LNvgAnzxEJrq7nO5bRZxAc7Us/OCLw3Vk33XwVBlDfPQ65UItr4py4tlJCA+aCQUTo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765923294; c=relaxed/simple; bh=XRM9ebZLofnlNG7c8Qp3cDo1buNW9ZaVDmkglZ3CIUg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ANdO7uCkMeoAMaMMwfaDabjSvzcZ7QeLEc5QPLfoorPYu0SdasHsY6UzedanDwvieyj9L7RvNLyfvDLOOgzVDCnWPmtHVZjPuZka0qvUTPoIV0NK3CrKrvVOpuKyqxMTWxN/5zuFL58pM2b2JLJNmthUctxUmi5tIsbJLK6SZtY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=jVDPbnZZ; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="jVDPbnZZ" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5BGHKXsN006963; Tue, 16 Dec 2025 22:14:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=0eulbv FY83Zr1QcyvkDK42S4t0eIAzUZ9Xf6vuTTqSk=; b=jVDPbnZZB3lLyoTOLiiNyg DhDy4lgSV/aRkscEfhJqSm/U8QSLTkaxI24aqgOR7WLJzDpvHsPJElOnD/KovwQE q5r3VZPoHcfvG0wNH7NqlAi+y/q8Yl0qI381qartoipiYLkjImW6Cm7ribX8nUos qIMXJWbgMDTvKikGKxgY+fdhwT/gQtlLkWYgfkVwXldJytd/QhHaIjFBx17Ok9Vk b9SSYRWzIzb0I34VlU2xnTqUKgJcFCeR+VkKm6mEm4Bd1bxveHK0Yjg23OABmg3w AD32DYjpmr3Rfp5UWoX5D3R6K7zeWe7VfqT33qsyWuW6zqnHXSXRQe0+gsQI9aZA == Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4b0xjm14tx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 Dec 2025 22:14:47 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5BGJXUUX014332; Tue, 16 Dec 2025 22:14:46 GMT Received: from smtprelay03.wdc07v.mail.ibm.com ([172.16.1.70]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4b1mpjxqu5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 16 Dec 2025 22:14:46 +0000 Received: from smtpav01.wdc07v.mail.ibm.com (smtpav01.wdc07v.mail.ibm.com [10.39.53.228]) by smtprelay03.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 5BGMESAs19792632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Dec 2025 22:14:28 GMT Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B74BF58063; Tue, 16 Dec 2025 22:14:44 +0000 (GMT) Received: from smtpav01.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 38F965805B; Tue, 16 Dec 2025 22:14:42 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav01.wdc07v.mail.ibm.com (Postfix) with ESMTP; Tue, 16 Dec 2025 22:14:42 +0000 (GMT) From: Niklas Schnelle Date: Tue, 16 Dec 2025 23:14:03 +0100 Subject: [PATCH v3 2/2] PCI/IOV: Fix race between SR-IOV enable/disable and hotplug 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 Message-Id: <20251216-revert_sriov_lock-v3-2-dac4925a7621@linux.ibm.com> References: <20251216-revert_sriov_lock-v3-0-dac4925a7621@linux.ibm.com> In-Reply-To: <20251216-revert_sriov_lock-v3-0-dac4925a7621@linux.ibm.com> To: Bjorn Helgaas Cc: Lukas Wunner , Keith Busch , Gerd Bayer , Matthew Rosato , Benjamin Block , Halil Pasic , Farhan Ali , Julian Ruess , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Niklas Schnelle X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1989; i=schnelle@linux.ibm.com; h=from:subject:message-id; bh=XRM9ebZLofnlNG7c8Qp3cDo1buNW9ZaVDmkglZ3CIUg=; b=owGbwMvMwCX2Wz534YHOJ2GMp9WSGDIdb55+eulJQJv5waoNG+aZXDmYWP2lw+Cwl+rxJ1lBf ZGOqkWpHaUsDGJcDLJiiiyLupz91hVMMd0T1N8BM4eVCWQIAxenAExE5h4jw8l2Oe7bH+9d3MyV dOHiliVfSl+GPOVedTnmlr3vrC2x9aUM/9RDRV+fqXeV6Pstf/O+/irxjIrN/9J8w2rsPqxa5nJ 2BjMA X-Developer-Key: i=schnelle@linux.ibm.com; a=openpgp; fpr=9DB000B2D2752030A5F72DDCAFE43F15E8C26090 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: xh1XA-mgLopcmNAa-5qHiLW-L6jnDsJX X-Authority-Analysis: v=2.4 cv=CLgnnBrD c=1 sm=1 tr=0 ts=6941d9d7 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=3aDRTbdq9RQ_ftGXbWIA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: xh1XA-mgLopcmNAa-5qHiLW-L6jnDsJX X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjEzMDAwOSBTYWx0ZWRfX3Z7bSmvaE6k6 XSC6AEVDFEy5mgOFAHL/U+LGw689YW7mxcb29mo2tKs61BoQeTmzGNsFeL0zdZtSXVhnzjDOypi zIsr8V32OMWdeRx9Dj/dRfoD9MtxL8M/6GxIP16JopqoIrMXEaxsAC6ruhtO44652LOJeU8aNZv O9gehDs7VwexZzn4ol1ZdRTNUqiU6kp6CxbLTQghNWr3DPYvmodyNEdQ8MUDr2cmHsBB/EAZFX5 6aBGpJ9fP1Xkbno8bVg7iPo1+0aomPeUZxVnGuMKlNXmZontl91vu6BpJgHNKPI8kLMoQeu77hU yAip0vWmLKTvLkLYur4LlXWAyXrMO9TdfamxWpnNwjn4H97hqwHFU8w3WV263R7x0EhyeoLJ+bu Rz+kYi3ldyxtJE1bvBQI3L5LftcHSQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-16_02,2025-12-16_05,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 lowpriorityscore=0 malwarescore=0 suspectscore=0 phishscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2512130009 Commit 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when enabling/disabling SR-IOV") tried to fix a race between the VF removal inside sriov_del_vfs() and concurrent hot unplug by taking the PCI rescan/remove lock in sriov_del_vfs(). Similarly the PCI rescan/remove lock was also taken in sriov_add_vfs() to protect addition of VFs. This approach however causes deadlock on trying to remove PFs with SR-IOV enabled because PFs disable SR-IOV during removal and this removal happens under the PCI rescan/remove lock. So the original fix had to be reverted. Instead of taking the PCI rescan/remove lock in sriov_add_vfs() and sriov_del_vfs(), fix the race that occurs with SR-IOV enable and disable vs hotplug higher up in the callchain by taking the lock in sriov_numvfs_store() before calling into the driver's sriov_configure() callback. Cc: stable@vger.kernel.org Fixes: 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when enabling/= disabling SR-IOV") Reported-by: Benjamin Block Reviewed-by: Benjamin Block Reviewed-by: Gerd Bayer Signed-off-by: Niklas Schnelle --- drivers/pci/iov.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 7de5b18647beb69127ba11234fb9f1dec9b50540..4a659c34935e116dd6d0b4ce42e= d12a1ba9418d1 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -495,7 +495,9 @@ static ssize_t sriov_numvfs_store(struct device *dev, =20 if (num_vfs =3D=3D 0) { /* disable VFs */ + pci_lock_rescan_remove(); ret =3D pdev->driver->sriov_configure(pdev, 0); + pci_unlock_rescan_remove(); goto exit; } =20 @@ -507,7 +509,9 @@ static ssize_t sriov_numvfs_store(struct device *dev, goto exit; } =20 + pci_lock_rescan_remove(); ret =3D pdev->driver->sriov_configure(pdev, num_vfs); + pci_unlock_rescan_remove(); if (ret < 0) goto exit; =20 --=20 2.51.0