Hello Bjorn!
I see following error message in dmesg which looks like a race condition:
sysfs: cannot create duplicate filename '/devices/platform/soc/d0070000.pcie/pci0000:00/0000:00:00.0/config'
I looked at it deeper and found out that in PCI subsystem code is race
condition between pci_bus_add_device() and pci_sysfs_init() calls. Both
of these functions calls pci_create_sysfs_dev_files() and calling this
function more times for same pci device throws above error message.
There can be two different race conditions:
1. pci_bus_add_device() called pcibios_bus_add_device() or
pci_fixup_device() but have not called pci_create_sysfs_dev_files() yet.
Meanwhile pci_sysfs_init() is running and pci_create_sysfs_dev_files()
was called for newly registered device. In this case function
pci_create_sysfs_dev_files() is called two times, ones from
pci_bus_add_device() and once from pci_sysfs_init().
2. pci_sysfs_init() is called. It first sets sysfs_initialized to 1
which unblock calling pci_create_sysfs_dev_files(). Then another bus
registers new PCI device and calls pci_bus_add_device() which calls
pci_create_sysfs_dev_files() and registers sysfs files. Function
pci_sysfs_init() continues execution and calls function
pci_create_sysfs_dev_files() also for this newly registered device. So
pci_create_sysfs_dev_files() is again called two times.
I workaround both race conditions I created following hack patch. After
applying it I'm not getting that 'sysfs: cannot create duplicate filename'
error message anymore.
Can you look at it how to fix both race conditions in proper way?
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 8e40b3e6da77..691be2258c4e 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -316,7 +316,7 @@ void pci_bus_add_device(struct pci_dev *dev)
*/
pcibios_bus_add_device(dev);
pci_fixup_device(pci_fixup_final, dev);
- pci_create_sysfs_dev_files(dev);
+ pci_create_sysfs_dev_files(dev, false);
pci_proc_attach_device(dev);
pci_bridge_d3_update(dev);
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 6d78df981d41..b0c4852a51dd 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1328,13 +1328,13 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
return retval;
}
-int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev)
+int __must_check pci_create_sysfs_dev_files(struct pci_dev *pdev, bool sysfs_initializing)
{
int retval;
int rom_size;
struct bin_attribute *attr;
- if (!sysfs_initialized)
+ if (!sysfs_initializing && !sysfs_initialized)
return -EACCES;
if (pdev->cfg_size > PCI_CFG_SPACE_SIZE)
@@ -1437,18 +1437,21 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
static int __init pci_sysfs_init(void)
{
struct pci_dev *pdev = NULL;
- int retval;
+ int retval = 0;
- sysfs_initialized = 1;
for_each_pci_dev(pdev) {
- retval = pci_create_sysfs_dev_files(pdev);
+ if (!pci_dev_is_added(pdev))
+ continue;
+ retval = pci_create_sysfs_dev_files(pdev, true);
if (retval) {
pci_dev_put(pdev);
- return retval;
+ goto out;
}
}
- return 0;
+out:
+ sysfs_initialized = 1;
+ return retval;
}
late_initcall(pci_sysfs_init);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 6d3f75867106..304294c7171e 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -19,7 +19,7 @@ bool pcie_cap_has_rtctl(const struct pci_dev *dev);
/* Functions internal to the PCI core code */
-int pci_create_sysfs_dev_files(struct pci_dev *pdev);
+int pci_create_sysfs_dev_files(struct pci_dev *pdev, bool sysfs_initializing);
void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
#if !defined(CONFIG_DMI) && !defined(CONFIG_ACPI)
static inline void pci_create_firmware_label_files(struct pci_dev *pdev)
