From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (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 7B64B1F130A; Tue, 2 Dec 2025 05:50:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764654645; cv=none; b=oaUm9FzUvX7Mnvkk1UlQEEDS2gWBclJw8ms3CGiqmdklj59Sda+1z++VafCzpUcUNH3wO8f7f977YLc4foH6EpjHF2nc/pEHgT0Jb2s7eAuNBIH21OBXzgjOTQ/oshZbZKr/5SJjdXGLyd97IBtuVQR789RputSuEP71QL7p9nY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764654645; c=relaxed/simple; bh=Vtmdw++S7pqLLxm6FQ7plKkNTdcUA34ahTlwE9H91Iw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pPxDr1QNFiNGtqNkBkVmoU3C65Vyzyhjx8FnpzYk2XYij4FXiqGGZNokMrtm3xVVCvoPcdJMrBhGJNSHnItHilX9P8MDM+Yg3iaGQYFpVOM0Ze9l0wE/C4Tt+QKLYs4SE70vbQyMfHWFx3PhW4s0EqO2yryDSM8GfcTw+cEJWH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=pX8gdY/x; arc=none smtp.client-ip=91.218.175.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="pX8gdY/x" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1764654631; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9h2CEg1WlZv1tOClOsV7Bzwrbcdvp6pClSclnRZaoeI=; b=pX8gdY/xTVUzgvR9DePNJG2wOT7qLHG5qKcBunbua3QmAQwQyqqx6CIjdufPJuYSxAkCVd BP2liEVb1kVbVUFtnPO4+ohs17oRfV+oVfxVjmuJSBkYuz4ZDLoNHYbq3UVcZMCfGcFlVv QRNdR3k2SfnG/s4WDyc2cb7eoleXRVw= Date: Mon, 1 Dec 2025 21:50:20 -0800 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 00/21] vfio/pci: Base support to preserve a VFIO device file across Live Update To: David Matlack Cc: Alex Williamson , Adithya Jayachandran , Alex Mastro , Alistair Popple , Andrew Morton , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Josh Hilke , Kevin Tian , kvm@vger.kernel.org, Leon Romanovsky , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-pci@vger.kernel.org, Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Philipp Stanner , Pratyush Yadav , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Tomita Moeko , Vipin Sharma , William Tu , Yi Liu , Yunxiang Li References: <20251126193608.2678510-1-dmatlack@google.com> <46bbdad1-486d-4cb1-915f-577b00de827f@linux.dev> <4998497c-87e8-4849-8442-b7281c627884@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zhu Yanjun In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 在 2025/12/1 9:36, David Matlack 写道: > On 2025-12-01 05:32 PM, David Matlack wrote: >> On 2025-12-01 09:16 AM, Zhu Yanjun wrote: >>> 在 2025/12/1 9:10, David Matlack 写道: >>>> On Mon, Dec 1, 2025 at 7:49 AM Zhu Yanjun wrote: >>>>> 在 2025/11/27 20:56, Zhu Yanjun 写道: >>>>>> Hi, David >>>>>> >>>>>> ERROR: modpost: "liveupdate_register_file_handler" [drivers/vfio/pci/ >>>>>> vfio-pci-core.ko] undefined! >>>>>> >>>>>> ERROR: modpost: "vfio_pci_ops" [drivers/vfio/pci/vfio-pci-core.ko] >>>>>> undefined! >>>>>> ERROR: modpost: "liveupdate_enabled" [drivers/vfio/pci/vfio-pci-core.ko] >>>>>> undefined! >>>>>> ERROR: modpost: "liveupdate_unregister_file_handler" [drivers/vfio/pci/ >>>>>> vfio-pci-core.ko] undefined! >>>>>> ERROR: modpost: "vfio_device_fops" [drivers/vfio/pci/vfio-pci-core.ko] >>>>>> undefined! >>>>>> ERROR: modpost: "vfio_pci_is_intel_display" [drivers/vfio/pci/vfio-pci- >>>>>> core.ko] undefined! >>>>>> ERROR: modpost: "vfio_pci_liveupdate_init" [drivers/vfio/pci/vfio- >>>>>> pci.ko] undefined! >>>>>> ERROR: modpost: "vfio_pci_liveupdate_cleanup" [drivers/vfio/pci/vfio- >>>>>> pci.ko] undefined! >>>>>> make[4]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1 >>>>>> make[3]: *** [Makefile:1960: modpost] Error 2 >>>>>> >>>>>> After I git clone the source code from the link https://github.com/ >>>>>> dmatlack/linux/tree/liveupdate/vfio/cdev/v1, >>>>>> >>>>>> I found the above errors when I built the source code. >>>>>> >>>>>> Perhaps the above errors can be solved by EXPORT_SYMBOL. >>>>>> >>>>>> But I am not sure if a better solution can solve the above problems or not. >>>>> I reviewed this patch series in detail. If I’m understanding it >>>>> correctly, there appears to be a cyclic dependency issue. Specifically, >>>>> some functions in kernel module A depend on kernel module B, while at >>>>> the same time certain functions in module B depend on module A. >>>>> >>>>> I’m not entirely sure whether this constitutes a real problem or if it’s >>>>> intentional design. >>>> Thanks for your report. Can you share the .config file you used to >>>> generate these errors? >>> >>> IIRC, I used FC 42 default config. Perhaps you can make tests with it. If >>> this problem can not be reproduced, I will share my config with you. >>> >> What does "FC 42 default config" mean? >> >> Either way I was able to reproduce the errors you posted above by >> changing CONFIG_VFIO_PCI{_CORE} from "y" to "m". >> >> To unblock building and testing this series you can change these configs >> from "m" to "y", or the following patch (which fixed things for me): > Oops, sorry, something went wrong when I posted that diff. Here's the > correct diff: > > diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile > index 929df22c079b..c2cca16e99a8 100644 > --- a/drivers/vfio/pci/Makefile > +++ b/drivers/vfio/pci/Makefile > @@ -2,11 +2,11 @@ > > vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o > vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o > -vfio-pci-core-$(CONFIG_LIVEUPDATE) += vfio_pci_liveupdate.o > obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o > > vfio-pci-y := vfio_pci.o > vfio-pci-$(CONFIG_VFIO_PCI_IGD) += vfio_pci_igd.o > +vfio-pci-$(CONFIG_LIVEUPDATE) += vfio_pci_liveupdate.o > obj-$(CONFIG_VFIO_PCI) += vfio-pci.o > > obj-$(CONFIG_MLX5_VFIO_PCI) += mlx5/ > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > index c5b5eb509474..b9805861763a 100644 > --- a/drivers/vfio/vfio_main.c > +++ b/drivers/vfio/vfio_main.c > @@ -1386,6 +1386,7 @@ const struct file_operations vfio_device_fops = { > .show_fdinfo = vfio_device_show_fdinfo, > #endif > }; > +EXPORT_SYMBOL_GPL(vfio_device_fops); > > /** > * vfio_file_is_valid - True if the file is valid vfio file > diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c > index 69298d82f404..c7a0c9c3b6a8 100644 > --- a/kernel/liveupdate/luo_core.c > +++ b/kernel/liveupdate/luo_core.c > @@ -256,6 +256,7 @@ bool liveupdate_enabled(void) > { > return luo_global.enabled; > } > +EXPORT_SYMBOL_GPL(liveupdate_enabled); > > /** > * DOC: LUO ioctl Interface > diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c > index fca3806dae28..9baa88966f04 100644 > --- a/kernel/liveupdate/luo_file.c > +++ b/kernel/liveupdate/luo_file.c > @@ -868,6 +868,7 @@ int liveupdate_register_file_handler(struct liveupdate_file_handler *fh) > luo_session_resume(); > return err; > } > +EXPORT_SYMBOL_GPL(liveupdate_register_file_handler); > > /** > * liveupdate_unregister_file_handler - Unregister a liveupdate file handler > @@ -913,3 +914,4 @@ int liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh) > liveupdate_test_register(fh); > return err; > } > +EXPORT_SYMBOL_GPL(liveupdate_unregister_file_handler); Hi, David Thanks. The above changes resolve the EXPORT_SYMBOL_GPL issue as well as the cyclic dependency problem. I recommend submitting this as a new commit, as it effectively addresses the issues present in the patch series. Yanjun.Zhu -- Best Regards, Yanjun.Zhu