From mboxrd@z Thu Jan 1 00:00:00 1970 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 F3D8B30BBA6; Wed, 19 Nov 2025 12:43:45 +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=1763556233; cv=none; b=WbjClS1VbWIFxVSZ8RcsoQub9DDeknP0gGFTgpMZK72G8eyVqbFbcWMu7bK+2ENHTGv+RhcJGgvQSoWYu07/I8Z8yy3UcypamnK4S7NwHJg6uiCNieC24oytQPl8ITSXyw+TkN3rAXEC9MlJ3EeIBJcu9U7CLnAd2AMllCjE+ag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763556233; c=relaxed/simple; bh=MayKp5+eHRdfu2fO7egFUne0TKfl1IZ9Rxo3gkN0D50=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=rARiSz/jOYuGp8ZP+opssHUWrLZi9jqRLj1x8FMQR7ySxnnwxaZNtmlVSAi1wDUT8wcz7Wu/yOzfPQdfEmRi02sKWP6ec+hIRDJEZ64DU77WBrH8udQp4c0EhaCRJ6YIi4Af1U7WHmC8sXqeHWrrViJ5x2kRsuiTFV2d79SfXhc= 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=iByY91DR; 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="iByY91DR" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5AJ8ODKw028819; Wed, 19 Nov 2025 12:43:27 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=uatKSU Vl/x45CPqU09/sirSD1yd4MjxDIBN8T5/c1eM=; b=iByY91DRLWOrBPDwg2R01T z5QoTmO05Y5rhi0fAdSglKidRkD6uI04EMvlLATvJTN3EXmmV+I4zZH8Qcyd16mb Pf/hgbHq+TQa57IHzfl5blHJoaOOd5LHQZpB6VrE4nDQ4weV3VexBH24bUPBGboK l1gRUtZa9XSf6NeIVd9JMKD3A4dt3f9LCbZjY/qQHeIIDEaSehuUWji3ToO1qrR2 zaVW1wda277Th4qCBGEHfpZ6yPz1lqcHc+q8i31yLHxsi+0WuaSQZQYKvh4HRgLk t6ZLwCRsVWEi50rKnGRhrmnOlvN3x7nqOyqUZBV4oyUERZa71kp82Wv416G3v00w == Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4aejmsqnkg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 19 Nov 2025 12:43:26 +0000 (GMT) Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5AJB3iE3030837; Wed, 19 Nov 2025 12:43:26 GMT Received: from smtprelay02.wdc07v.mail.ibm.com ([172.16.1.69]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4af47y0ref-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 19 Nov 2025 12:43:26 +0000 Received: from smtpav05.wdc07v.mail.ibm.com (smtpav05.wdc07v.mail.ibm.com [10.39.53.232]) by smtprelay02.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 5AJChOKO19858160 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 19 Nov 2025 12:43:25 GMT Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DA1F05805D; Wed, 19 Nov 2025 12:43:24 +0000 (GMT) Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 154A758043; Wed, 19 Nov 2025 12:43:22 +0000 (GMT) Received: from [9.111.50.182] (unknown [9.111.50.182]) by smtpav05.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 19 Nov 2025 12:43:21 +0000 (GMT) Message-ID: <440934261b39a033b20063d6a598d06bb343caad.camel@linux.ibm.com> Subject: Re: [PATCH v2 0/2] PCI/IOV: Fix deadlock when removing PF with enabled SR-IOV From: Niklas Schnelle 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, regressions Date: Wed, 19 Nov 2025 13:43:21 +0100 In-Reply-To: <20251119-revert_sriov_lock-v2-0-ea50eb1e8f96@linux.ibm.com> References: <20251119-revert_sriov_lock-v2-0-ea50eb1e8f96@linux.ibm.com> Autocrypt: addr=schnelle@linux.ibm.com; prefer-encrypt=mutual; keydata=mQINBGHm3M8BEAC+MIQkfoPIAKdjjk84OSQ8erd2OICj98+GdhMQpIjHXn/RJdCZLa58k /ay5x0xIHkWzx1JJOm4Lki7WEzRbYDexQEJP0xUia0U+4Yg7PJL4Dg/W4Ho28dRBROoJjgJSLSHwc 3/1pjpNlSaX/qg3ZM8+/EiSGc7uEPklLYu3gRGxcWV/944HdUyLcnjrZwCn2+gg9ncVJjsimS0ro/ 2wU2RPE4ju6NMBn5Go26sAj1owdYQQv9t0d71CmZS9Bh+2+cLjC7HvyTHKFxVGOznUL+j1a45VrVS XQ+nhTVjvgvXR84z10bOvLiwxJZ/00pwNi7uCdSYnZFLQ4S/JGMs4lhOiCGJhJ/9FR7JVw/1t1G9a UlqVp23AXwzbcoV2fxyE/CsVpHcyOWGDahGLcH7QeitN6cjltf9ymw2spBzpRnfFn80nVxgSYVG1d w75ksBAuQ/3e+oTQk4GAa2ShoNVsvR9GYn7rnsDN5pVILDhdPO3J2PGIXa5ipQnvwb3EHvPXyzakY tK50fBUPKk3XnkRwRYEbbPEB7YT+ccF/HioCryqDPWUivXF8qf6Jw5T1mhwukUV1i+QyJzJxGPh19 /N2/GK7/yS5wrt0Lwxzevc5g+jX8RyjzywOZGHTVu9KIQiG8Pqx33UxZvykjaqTMjo7kaAdGEkrHZ dVHqoPZwhCsgQARAQABtChOaWtsYXMgU2NobmVsbGUgPHNjaG5lbGxlQGxpbnV4LmlibS5jb20+iQ JXBBMBCABBAhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAhkBFiEEnbAAstJ1IDCl9y3cr+Q/Fej CYJAFAmesutgFCQenEYkACgkQr+Q/FejCYJDIzA//W5h3t+anRaztihE8ID1c6ifS7lNUtXr0wEKx Qm6EpDQKqFNP+n3R4A5w4gFqKv2JpYQ6UJAAlaXIRTeT/9XdqxQlHlA20QWI7yrJmoYaF74ZI9s/C 8aAxEzQZ64NjHrmrZ/N9q8JCTlyhk5ZEV1Py12I2UH7moLFgBFZsPlPWAjK2NO/ns5UJREAJ04pR9 XQFSBm55gsqkPp028cdoFUD+IajGtW7jMIsx/AZfYMZAd30LfmSIpaPAi9EzgxWz5habO1ZM2++9e W6tSJ7KHO0ZkWkwLKicrqpPvA928eNPxYtjkLB2XipdVltw5ydH9SLq0Oftsc4+wDR8TqhmaUi8qD Fa2I/0NGwIF8hjwSZXtgJQqOTdQA5/6voIPheQIi0NBfUr0MwboUIVZp7Nm3w0QF9SSyTISrYJH6X qLp17NwnGQ9KJSlDYCMCBJ+JGVmlcMqzosnLli6JszAcRmZ1+sd/f/k47Fxy1i6o14z9Aexhq/UgI 5InZ4NUYhf5pWflV41KNupkS281NhBEpChoukw25iZk0AsrukpJ74x69MJQQO+/7PpMXFkt0Pexds XQrtsXYxLDQk8mgjlgsvWl0xlk7k7rddN1+O/alcv0yBOdvlruirtnxDhbjBqYNl8PCbfVwJZnyQ4 SAX2S9XiGeNtWfZ5s2qGReyAcd2nBna0KU5pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNjaG5lbGxlQ GlibS5jb20+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAAstJ1IDCl9y 3cr+Q/FejCYJAFAmesuuEFCQenEYkACgkQr+Q/FejCYJCosA/9GCtbN8lLQkW71n/CHR58BAA5ct1 KRYiZNPnNNAiAzjvSb0ezuRVt9H0bk/tnj6pPj0zdyU2bUj9Ok3lgocWhsF2WieWbG4dox5/L1K28 qRf3p+vdPfu7fKkA1yLE5GXffYG3OJnqR7OZmxTnoutj81u/tXO95JBuCSJn5oc5xMQvUUFzLQSbh prIWxcnzQa8AHJ+7nAbSiIft/+64EyEhFqncksmzI5jiJ5edABiriV7bcNkK2d8KviUPWKQzVlQ3p LjRJcJJHUAFzsZlrsgsXyZLztAM7HpIA44yo+AVVmcOlmgPMUy+A9n+0GTAf9W3y36JYjTS+ZcfHU KP+y1TRGRzPrFgDKWXtsl1N7sR4tRXrEuNhbsCJJMvcFgHsfni/f4pilabXO1c5Pf8fiXndCz04V8 ngKuz0aG4EdLQGwZ2MFnZdyf3QbG3vjvx7XDlrdzH0wUgExhd2fHQ2EegnNS4gNHjq82uLPU0hfcr obuI1D74nV0BPDtr7PKd2ryb3JgjUHKRKwok6IvlF2ZHMMXDxYoEvWlDpM1Y7g81NcKoY0BQ3ClXi a7vCaqAAuyD0zeFVGcWkfvxYKGqpj8qaI/mA8G5iRMTWUUUROy7rKJp/y2ioINrCul4NUJUujfx4k 7wFU11/YNAzRhQG4MwoO5e+VY66XnAd+XPyBIlvy0K05pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNj aG5lbGxlQGdtYWlsLmNvbT6JAlQEEwEIAD4CGwEFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQSds ACy0nUgMKX3Ldyv5D8V6MJgkAUCZ6y64QUJB6cRiQAKCRCv5D8V6MJgkEr/D/9iaYSYYwlmTJELv+ +EjsIxXtneKYpjXEgNnPwpKEXNIpuU/9dcVDcJ10MfvWBPi3sFbIzO9ETIRyZSgrjQxCGSIhlbom4 D8jVzTA698tl9id0FJKAi6T0AnBF7CxyqofPUzAEMSj9ynEJI/Qu8pHWkVp97FdJcbsho6HNMthBl +Qgj9l7/Gm1UW3ZPvGYgU75uB/mkaYtEv0vYrSZ+7fC2Sr/O5SM2SrNk+uInnkMBahVzCHcoAI+6O Enbag+hHIeFbqVuUJquziiB/J4Z2yT/3Ps/xrWAvDvDgdAEr7Kn697LLMRWBhGbdsxdHZ4ReAhc8M 8DOcSWX7UwjzUYq7pFFil1KPhIkHctpHj2Wvdnt+u1F9fN4e3C6lckUGfTVd7faZ2uDoCCkJAgpWR 10V1Q1Cgl09VVaoi6LcGFPnLZfmPrGYiDhM4gyDDQJvTmkB+eMEH8u8V1X30nCFP2dVvOpevmV5Uk onTsTwIuiAkoTNW4+lRCFfJskuTOQqz1F8xVae8KaLrUt2524anQ9x0fauJkl3XdsVcNt2wYTAQ/V nKUNgSuQozzfXLf+cOEbV+FBso/1qtXNdmAuHe76ptwjEfBhfg8L+9gMUthoCR94V0y2+GEzR5nlD 5kfu8ivV/gZvij+Xq3KijIxnOF6pd0QzliKadaFNgGw4FoUeZo0rQhTmlrbGFzIFNjaG5lbGxlIDx uaWtzQGtlcm5lbC5vcmc+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAA stJ1IDCl9y3cr+Q/FejCYJAFAmesuuEFCQenEYkACgkQr+Q/FejCYJC6yxAAiQQ5NAbWYKpkxxjP/ AajXheMUW8EtK7EMJEKxyemj40laEs0wz9owu8ZDfQl4SPqjjtcRzUW6vE6JvfEiyCLd8gUFXIDMS l2hzuNot3sEMlER9kyVIvemtV9r8Sw1NHvvCjxOMReBmrtg9ooeboFL6rUqbXHW+yb4GK+1z7dy+Q 9DMlkOmwHFDzqvsP7eGJN0xD8MGJmf0L5LkR9LBc+jR78L+2ZpKA6P4jL53rL8zO2mtNQkoUO+4J6 0YTknHtZrqX3SitKEmXE2Is0Efz8JaDRW41M43cE9b+VJnNXYCKFzjiqt/rnqrhLIYuoWCNzSJ49W vt4hxfqh/v2OUcQCIzuzcvHvASmt049ZyGmLvEz/+7vF/Y2080nOuzE2lcxXF1Qr0gAuI+wGoN4gG lSQz9pBrxISX9jQyt3ztXHmH7EHr1B5oPus3l/zkc2Ajf5bQ0SE7XMlo7Pl0Xa1mi6BX6I98CuvPK SA1sQPmo+1dQYCWmdQ+OIovHP9Nx8NP1RB2eELP5MoEW9eBXoiVQTsS6g6OD3rH7xIRxRmuu42Z5e 0EtzF51BjzRPWrKSq/mXIbl5nVW/wD+nJ7U7elW9BoJQVky03G0DhEF6fMJs08DGG3XoKw/CpGtMe 2V1z/FRotP5Fkf5VD3IQGtkxSnO/awtxjlhytigylgrZ4wDpSE= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.1 (3.58.1-1.fc43) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: KrbGUF3L_wBztBdNddO69z87ua36D-Np X-Authority-Analysis: v=2.4 cv=Rv3I7SmK c=1 sm=1 tr=0 ts=691dbb6e cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=eTQjpDOuu0DvYVNBffgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: KrbGUF3L_wBztBdNddO69z87ua36D-Np X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfX4wCULyPnPJMD td9x9F/EStABXsL24fZ32x+eYk2fhJEoq9tfWy556ZijFCrjIt0u99+1KDzsQ71v2VPnsUENyN8 XUJqMk2Uz40BorhpyMJ9LHZfCuLfRtgAFjBw+NPn0elxWhEAi2k3YX7Z6EKayC47L4fxRGIUcb5 9ilz1YuRVbVMWcQUv71oNnK7rxC6RoEeOjFpD8aA8Nn68HHTMMEvb1d50xNPyoP030GkGAbdTn0 bK/hJHneS8rK+g5+P6rKU+TEAHdJj11GKGcj7Z1eUEHRug8LhN8sexIeQVWAENhWU9seLVJjSxT /4ARRooLiEKTrMgmi1ei1VbG0Qu27AF+1xqyqecsiDKEMJqrhu9TIZw3Gm34bP8Fv39WO4OU+T/ D1lAtaNLf90+0V4Mc7D+R2bUWAwHhg== 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=2025-11-19_03,2025-11-18_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 clxscore=1011 phishscore=0 priorityscore=1501 spamscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 On Wed, 2025-11-19 at 13:34 +0100, Niklas Schnelle wrote: > Hi Bjorn, >=20 > Doing additional testing for a distribution backport of commit > 05703271c3cd ("PCI/IOV: Add PCI rescan-remove locking when > enabling/disabling SR-IOV") Benjamin found a hang with s390's > recover attribute. Further investigation showed this to be a deadlock by > recursively trying to take pci_rescan_remove lock when removing a PF > with enabled SR-IOV. >=20 > The issue can be reproduced on both s390 and x86_64 with: >=20 > $ echo > /sys/bus/pci/devices//sriov_numvfs > $ echo 1 > /sys/bus/pci/devices//remove >=20 > As this seems worse than the original, hard to hit, race fixed by the > cited commit I think we first want to revert the broken fix. >=20 > Following that patch 2 attempts to fix the original issue by taking the > PCI rescan/remove lock directly before calling into the driver's > sriov_configure() callback enforcing the rule that this should only > be called with the pci_rescan_remove_lock held. >=20 > Thanks, > Niklas >=20 > Signed-off-by: Niklas Schnelle > --- > Changes in v2: > - Collected R-b from Benjamin > - Link to v1: https://lore.kernel.org/r/20251030-revert_sriov_lock-v1-0-7= 0f82ade426f@linux.ibm.com >=20 > --- > Niklas Schnelle (2): > Revert "PCI/IOV: Add PCI rescan-remove locking when enabling/disabl= ing SR-IOV" > PCI/IOV: Fix race between SR-IOV enable/disable and hotplug >=20 > drivers/pci/iov.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > --- > base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa > change-id: 20251029-revert_sriov_lock-aef4557f360f >=20 > Best regards, Since this is really a regression without a separate report, yet this has a description and reproducer I'm just adding this here: #regzbot ^introduced: 05703271c3cd