From nobody Sun Oct 5 07:21:22 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 8AE0B214813; Thu, 7 Aug 2025 13:11:46 +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=1754572308; cv=none; b=dLdAOcF+1Wy9shSLizxlDNIZ8PmL+IcFXMuXZeDnGWazd5QAUdHr+WVWkXxFTmq8LVrLtpuvDwJeJQgUVRob4k69/6Wcck87Re7LpQv9plmMSVzZIx7+cxrZPuYXbkr/4oSnrqTsAKFzNGfpNRJ8WjG84Vm9xcloU29/d/TUcVI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754572308; c=relaxed/simple; bh=m26lHftS7IlP7iMGha5zcOVxy2cQ5Y4OefzgkzmDR7k=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=R3IdiuXbUd5P4Y7+DCESIRSOFbmJIqBQN+YQ3lU/N/mwGpVxenlM0VrFnKYZdk2w2GEv6kLU/clf0bvEh52hnEIhjRADGOSZXRAEAW5nNpvlmPN5SWzeKi3BdNBFZ3O5IfsWJ8PiBIo9F4zj/Mi74jraHf4a3oOnDeNcQ4yryd0= 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=FK1nzQ7h; 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="FK1nzQ7h" Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5776AYew021685; Thu, 7 Aug 2025 13:11:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:message-id:mime-version :subject:to; s=pp1; bh=Hq6l2Vqaq2ClYP24fuqKUawfQczgoqoysESf8KFRt i0=; b=FK1nzQ7hyINYu6PIQ6E99KsFxdmJkNbl3Rl7REfZVeB9Iaw2XadFFNHbB y7CMqFWHFeQDs3gZu6zAqs9VZxFyS9V5S5StF5350uhg8g/WRaIj0xGciMPSLzEV t0ib8lckmzkn8e8Mj84K5F4zbPaSliJ/5x4x0MBbThLt7N2l2HEBOyZms6mx38Iq +ZHQTBkN1AGytgp1WGS/tjNYG1p3fCzbT7CItEaEaocswNHdHIFppagG+nzLcVfv px2dx6PNEhduOXv0npgxONkApz799J3Wgsq4L52n5C44S+R2GCZaT8PmrV95ZSc9 APvsZJw4ByRMzd1GK0YRxBmMj5j9g== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48bq63a48s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Aug 2025 13:11:36 +0000 (GMT) Received: from m0356516.ppops.net (m0356516.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 577D9gQ0011197; Thu, 7 Aug 2025 13:11:35 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 48bq63a48p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Aug 2025 13:11:35 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5779eev2022647; Thu, 7 Aug 2025 13:11:34 GMT Received: from smtprelay05.fra02v.mail.ibm.com ([9.218.2.225]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 48bpwqgqtr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Aug 2025 13:11:34 +0000 Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay05.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 577DBVJv53150180 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 7 Aug 2025 13:11:31 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E889920043; Thu, 7 Aug 2025 13:11:30 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B4D3A20040; Thu, 7 Aug 2025 13:11:30 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.152.85.9]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 7 Aug 2025 13:11:30 +0000 (GMT) From: Gerd Bayer To: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Mark Bloch , Jakub Kicinski , Paolo Abeni , Moshe Shemesh , Shay Drori Cc: Niklas Schnelle , Alexandra Winter , Gerd Bayer , Andrew Lunn , "David S. Miller" , Eric Dumazet , Yuanyuan Zhong , Mohamed Khalfella , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net] net/mlx5: Avoid deadlock between PCI error recovery and health reporter Date: Thu, 7 Aug 2025 15:11:30 +0200 Message-ID: <20250807131130.4056349-1-gbayer@linux.ibm.com> X-Mailer: git-send-email 2.48.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=NInV+16g c=1 sm=1 tr=0 ts=6894a608 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=2OwXVqhp2XgA:10 a=sWKEhP36mHoA:10 a=VnNF1IyMAAAA:8 a=bw0WNZ3Bkwh0Ihv45_YA:9 X-Proofpoint-GUID: uvjlW20QgFidYsL1fE9SvzET59v4Ld5R X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA3MDEwMyBTYWx0ZWRfX/MXrqH9WlIQp lWNNAcnNoBsqPjhog3y1ehaA3BpAZW3FR1q9mHd8IJwYPgKuKYt24A/Hj6NS9Me8Ud7O0wUImCF sfvZqWzt1mU+ybNt9Qk3GXEy7YqW/m/zYQZaWzvHYuqB+ZISkxr9tu/7Y4mEAyUab6Q3+xx3eN9 UtpYcT9FjHTPGyW2Jn4gMs3fVJ++FI9Jj4332lHSg33/Gw+Dox/70Teg5QB6MlWyml9wI9ciP/W dg30zllj4gMxAk0ytXSRLh7UUUBK+y3FW6zo4tHJMrhtoO+sYdtJUgIEA5DRO+6m5A6zT0u+RK/ x5sG07h+R4xEjz7IrbN3j+rSG9xL1Il/0pH6rGHEf6BN+4Gv/V+BRg2RdMfMnE7O//sqgtDM2NY zByHx093AOjhmJHRCocTuUD81FNb6Rze2HaklRgKYORESUAFFr8vqIBGlGgPzTy+Thx+3hDu X-Proofpoint-ORIG-GUID: xNt2Ifd1HMgDAfVOfXdai4ywFg0ik2Yk X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-07_02,2025-08-06_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 suspectscore=0 impostorscore=0 mlxlogscore=999 lowpriorityscore=0 malwarescore=0 clxscore=1011 adultscore=0 mlxscore=0 bulkscore=0 priorityscore=1501 spamscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508070103 Content-Type: text/plain; charset="utf-8" During error recovery testing a pair of tasks was reported to be hung due to a dead-lock situation: - mlx5_unload_one() trying to acquire devlink lock while the PCI error recovery code had acquired the pci_cfg_access_lock(). - mlx5_crdump_collect() trying to acquire the pci_cfg_access_lock() while devlink_health_report() had acquired the devlink lock. Move the check for pci_channel_offline prior to acquiring the pci_cfg_access_lock in mlx5_vsc_gw_lock since collecting the crdump will fail anyhow while PCI error recovery is running. Fixes: 33afbfcc105a ("net/mlx5: Stop waiting for PCI if pci channel is offl= ine") Signed-off-by: Gerd Bayer --- Hi all, while the initial hit was recorded during "random" testing, where PCI error recovery and poll_health() tripped almost simultaneously, I found a way to reproduce a very similar hang at will on s390: Inject a PCI error recovery event on a Physical Function with zpcictl --reset-fw then request a crdump with devlink health dump show pci/ reporter fw_fatal With the patch applied I didn't get the hang but kernel logs showed: [ 792.885743] mlx5_core 000a:00:00.0: mlx5_crdump_collect:51:(pid 1415): c= rdump: failed to lock vsc gw err -13 and the crdump request ended with: kernel answers: Permission denied Thanks, Gerd --- drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c b/driver= s/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c index 432c98f2626d..d2d3b57a57d5 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c @@ -73,16 +73,15 @@ int mlx5_vsc_gw_lock(struct mlx5_core_dev *dev) u32 lock_val; int ret; =20 + if (pci_channel_offline(dev->pdev)) + return -EACCES; + pci_cfg_access_lock(dev->pdev); do { if (retries > VSC_MAX_RETRIES) { ret =3D -EBUSY; goto pci_unlock; } - if (pci_channel_offline(dev->pdev)) { - ret =3D -EACCES; - goto pci_unlock; - } =20 /* Check if semaphore is already locked */ ret =3D vsc_read(dev, VSC_SEMAPHORE_OFFSET, &lock_val); --=20 2.48.1