On 12/1/25 9:44 AM, Pasha Tatashin wrote:
On Mon, Dec 1, 2025 at 12:36 PM David Matlack <[email protected]> wrote:
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 <[email protected]> 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);
Sure. Exactly. The above is the same with my solution. But after that
EXPORT_SYMBOL_GPL, a cyclic dependency issue will occur.
Yanjun.Zhu
Please add the EXPORT_SYMBOL_GPL() to the public LUO API as needed, I
was asked to stay conservative and not export until it is actually
needed by modules.
