From 5b0948dfe138f0837699f46f5877f4f81c252dac Mon Sep 17 00:00:00 2001 From: Emil Tantilov Date: Fri, 6 Jan 2017 13:59:08 -0800 Subject: [PATCH] PCI: Lock each enable/disable num_vfs operation in sysfs Enabling/disabling SRIOV via sysfs by echo-ing multiple values simultaneously: # echo 63 > /sys/class/net/ethX/device/sriov_numvfs& # echo 63 > /sys/class/net/ethX/device/sriov_numvfs # sleep 5 # echo 0 > /sys/class/net/ethX/device/sriov_numvfs& # echo 0 > /sys/class/net/ethX/device/sriov_numvfs results in the following bug: kernel BUG at drivers/pci/iov.c:495! invalid opcode: 0000 [#1] SMP CPU: 1 PID: 8050 Comm: bash Tainted: G W 4.9.0-rc7-net-next #2092 RIP: 0010:[] [] pci_iov_release+0x57/0x60 Call Trace: [] pci_release_dev+0x26/0x70 [] device_release+0x3e/0xb0 [] kobject_cleanup+0x67/0x180 [] kobject_put+0x2d/0x60 [] put_device+0x17/0x20 [] pci_dev_put+0x1a/0x20 [] pci_get_dev_by_id+0x5b/0x90 [] pci_get_subsys+0x35/0x40 [] pci_get_device+0x18/0x20 [] pci_get_domain_bus_and_slot+0x2b/0x60 [] pci_iov_remove_virtfn+0x57/0x180 [] pci_disable_sriov+0x65/0x140 [] ixgbe_disable_sriov+0xc7/0x1d0 [ixgbe] [] ixgbe_pci_sriov_configure+0x3d/0x170 [ixgbe] [] sriov_numvfs_store+0xdc/0x130 ... RIP [] pci_iov_release+0x57/0x60 Use the existing mutex lock to protect each enable/disable operation. Signed-off-by: Emil Tantilov Signed-off-by: Bjorn Helgaas Reviewed-by: Gavin Shan CC: Alexander Duyck --- drivers/pci/iov.c | 7 ------- drivers/pci/pci-sysfs.c | 23 ++++++++++++++++------- drivers/pci/pci.h | 2 +- 3 files changed, 17 insertions(+), 15 deletions(-) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 47227820406d..2479ae876482 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -124,7 +124,6 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset) struct pci_sriov *iov = dev->sriov; struct pci_bus *bus; - mutex_lock(&iov->dev->sriov->lock); bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id)); if (!bus) goto failed; @@ -162,7 +161,6 @@ int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset) __pci_reset_function(virtfn); pci_device_add(virtfn, virtfn->bus); - mutex_unlock(&iov->dev->sriov->lock); pci_bus_add_device(virtfn); sprintf(buf, "virtfn%u", id); @@ -181,12 +179,10 @@ failed2: sysfs_remove_link(&dev->dev.kobj, buf); failed1: pci_dev_put(dev); - mutex_lock(&iov->dev->sriov->lock); pci_stop_and_remove_bus_device(virtfn); failed0: virtfn_remove_bus(dev->bus, bus); failed: - mutex_unlock(&iov->dev->sriov->lock); return rc; } @@ -195,7 +191,6 @@ void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset) { char buf[VIRTFN_ID_LEN]; struct pci_dev *virtfn; - struct pci_sriov *iov = dev->sriov; virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus), pci_iov_virtfn_bus(dev, id), @@ -218,10 +213,8 @@ void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset) if (virtfn->dev.kobj.sd) sysfs_remove_link(&virtfn->dev.kobj, "physfn"); - mutex_lock(&iov->dev->sriov->lock); pci_stop_and_remove_bus_device(virtfn); virtfn_remove_bus(dev->bus, virtfn->bus); - mutex_unlock(&iov->dev->sriov->lock); /* balance pci_get_domain_bus_and_slot() */ pci_dev_put(virtfn); diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 066628776e1b..25d010d449a3 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -472,6 +472,7 @@ static ssize_t sriov_numvfs_store(struct device *dev, const char *buf, size_t count) { struct pci_dev *pdev = to_pci_dev(dev); + struct pci_sriov *iov = pdev->sriov; int ret; u16 num_vfs; @@ -482,38 +483,46 @@ static ssize_t sriov_numvfs_store(struct device *dev, if (num_vfs > pci_sriov_get_totalvfs(pdev)) return -ERANGE; + mutex_lock(&iov->dev->sriov->lock); + if (num_vfs == pdev->sriov->num_VFs) - return count; /* no change */ + goto exit; /* is PF driver loaded w/callback */ if (!pdev->driver || !pdev->driver->sriov_configure) { dev_info(&pdev->dev, "Driver doesn't support SRIOV configuration via sysfs\n"); - return -ENOSYS; + ret = -ENOENT; + goto exit; } if (num_vfs == 0) { /* disable VFs */ ret = pdev->driver->sriov_configure(pdev, 0); - if (ret < 0) - return ret; - return count; + goto exit; } /* enable VFs */ if (pdev->sriov->num_VFs) { dev_warn(&pdev->dev, "%d VFs already enabled. Disable before enabling %d VFs\n", pdev->sriov->num_VFs, num_vfs); - return -EBUSY; + ret = -EBUSY; + goto exit; } ret = pdev->driver->sriov_configure(pdev, num_vfs); if (ret < 0) - return ret; + goto exit; if (ret != num_vfs) dev_warn(&pdev->dev, "%d VFs requested; only %d enabled\n", num_vfs, ret); +exit: + mutex_unlock(&iov->dev->sriov->lock); + + if (ret < 0) + return ret; + return count; } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index cb17db242f30..8dd38e69d6f2 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -270,7 +270,7 @@ struct pci_sriov { u16 driver_max_VFs; /* max num VFs driver supports */ struct pci_dev *dev; /* lowest numbered PF */ struct pci_dev *self; /* this PF */ - struct mutex lock; /* lock for VF bus */ + struct mutex lock; /* lock for setting sriov_numvfs in sysfs */ resource_size_t barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */ };