[Intel-wired-lan] [PATCH 2/2] PCI: lock each enable/disable num_vfs operation in sysfs
Emil Tantilov
emil.s.tantilov at intel.com
Wed Jan 4 00:48:31 UTC 2017
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:[<ffffffff813b1647>]
[<ffffffff813b1647>] pci_iov_release+0x57/0x60
Call Trace:
[<ffffffff81391726>] pci_release_dev+0x26/0x70
[<ffffffff8155be6e>] device_release+0x3e/0xb0
[<ffffffff81365ee7>] kobject_cleanup+0x67/0x180
[<ffffffff81365d9d>] kobject_put+0x2d/0x60
[<ffffffff8155bc27>] put_device+0x17/0x20
[<ffffffff8139c08a>] pci_dev_put+0x1a/0x20
[<ffffffff8139cb6b>] pci_get_dev_by_id+0x5b/0x90
[<ffffffff8139cca5>] pci_get_subsys+0x35/0x40
[<ffffffff8139ccc8>] pci_get_device+0x18/0x20
[<ffffffff8139ccfb>] pci_get_domain_bus_and_slot+0x2b/0x60
[<ffffffff813b09e7>] pci_iov_remove_virtfn+0x57/0x180
[<ffffffff813b0b95>] pci_disable_sriov+0x65/0x140
[<ffffffffa00a1af7>] ixgbe_disable_sriov+0xc7/0x1d0 [ixgbe]
[<ffffffffa00a1e9d>] ixgbe_pci_sriov_configure+0x3d/0x170 [ixgbe]
[<ffffffff8139d28c>] sriov_numvfs_store+0xdc/0x130
...
RIP [<ffffffff813b1647>] pci_iov_release+0x57/0x60
Use the existing mutex lock to protect each enable/disable operation.
CC: Alexander Duyck <alexander.h.duyck at intel.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov at intel.com>
---
drivers/pci/pci-sysfs.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 0666287..5b54cf5 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -472,7 +472,9 @@ 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;
ret = kstrtou16(buf, 0, &num_vfs);
@@ -482,38 +484,46 @@ 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 = -EINVAL;
+ 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;
}
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