hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8BLQX CVE: NA
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"echo sriov_totalvfs > /sys/bus/pci/devices/$PF_BDF/sriov_numvfs" concurrently may cause the following warnings:
Warning 1: sysfs: cannot create duplicate filename '/devices/pci0000:95/0000:95:00.0/pci_bus/0000:97'
Call trace: dump_backtrace+0x0/0x200 show_stack+0x20/0x30 dump_stack+0xf0/0x138 sysfs_warn_dup+0x6c/0x90 sysfs_create_dir_ns+0xf8/0x11c create_dir+0x30/0x18c kobject_add_internal+0x5c/0x190 kobject_add+0x98/0x110 device_add+0x100/0x4a0 device_register+0x28/0x40 pci_alloc_child_bus+0x184/0x24c pci_add_new_bus+0x20/0xa4 pci_iov_add_virtfn+0x2a8/0x31c sriov_enable+0x20c/0x4d0 pci_enable_sriov+0x38/0x50 virtio_pci_sriov_configure+0x3c/0xf4 [virtio_pci] sriov_numvfs_store+0xb0/0x1b0 dev_attr_store+0x20/0x34 sysfs_kf_write+0x4c/0x5c kernfs_fop_write_iter+0x130/0x1c0 new_sync_write+0xf0/0x194 vfs_write+0x224/0x2c0 ksys_write+0x74/0x104 __arm64_sys_write+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0xa4 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180
The reason is that different VFs may create the same pci bus number and try to add new bus concurrently in virtfn_add_bus.
Warning 2: proc_dir_entry 'pci/0000:97' already registered
Call trace: proc_register+0x100/0x190 proc_mkdir+0x6c/0xa0 pci_proc_attach_device+0xfc/0x120 pci_bus_add_device+0x40/0xd0 pci_iov_add_virtfn+0x2c8/0x31c sriov_enable+0x20c/0x4d0 pci_enable_sriov+0x38/0x50 virtio_pci_sriov_configure+0x3c/0xf4 [virtio_pci] sriov_numvfs_store+0xb0/0x1b0 dev_attr_store+0x20/0x34 sysfs_kf_write+0x4c/0x5c kernfs_fop_write_iter+0x130/0x1c0 new_sync_write+0xf0/0x194 vfs_write+0x224/0x2c0 ksys_write+0x74/0x104 __arm64_sys_write+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x1bc do_el0_svc+0x2c/0xa4 el0_svc+0x20/0x30 el0_sync_handler+0xb0/0xb4 el0_sync+0x160/0x180
The reason is that different VFs may create '/proc/bus/pci/bus_number' directory using the same bus number in pci_proc_attach_device concurrently.
Mutex lock can avoid potential conflict. With the patch below the warnings above are no longer appear.
Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- drivers/pci/iov.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 4afd4ee4f7f0..958f349345ca 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -16,6 +16,8 @@
#define VIRTFN_ID_LEN 16
+static DEFINE_MUTEX(pci_sriov_numvfs_lock); + int pci_iov_virtfn_bus(struct pci_dev *dev, int vf_id) { if (!dev->is_physfn) @@ -299,6 +301,7 @@ static ssize_t sriov_numvfs_store(struct device *dev, if (num_vfs > pci_sriov_get_totalvfs(pdev)) return -ERANGE;
+ mutex_lock(&pci_sriov_numvfs_lock); device_lock(&pdev->dev);
if (num_vfs == pdev->sriov->num_VFs) @@ -335,6 +338,7 @@ static ssize_t sriov_numvfs_store(struct device *dev,
exit: device_unlock(&pdev->dev); + mutex_unlock(&pci_sriov_numvfs_lock);
if (ret < 0) return ret;