diff options
| author | Christoph Hellwig <hch@lst.de> | 2017-06-01 14:10:37 +0300 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2017-06-15 05:49:13 +0300 |
| commit | b014e96d1abbd67404bbe2018937b46466299e9e (patch) | |
| tree | 38b5d4431d8a8305423cc010443ceecb8ad8bde4 /drivers/pci/pci.c | |
| parent | 17530e71e0166a37f8e20a9b7bcf1d50ae3cff8e (diff) | |
| download | linux-b014e96d1abbd67404bbe2018937b46466299e9e.tar.xz | |
PCI: Protect pci_error_handlers->reset_notify() usage with device_lock()
Every method in struct device_driver or structures derived from it like
struct pci_driver MUST provide exclusion vs the driver's ->remove() method,
usually by using device_lock().
Protect use of pci_error_handlers->reset_notify() by holding the device
lock while calling it.
Note:
- pci_dev_lock() calls device_lock() in addition to blocking user-space
config accesses.
- pci_err_handlers->reset_notify() is used inside
pci_dev_save_and_disable() and pci_dev_restore(). We could hold the
device lock directly in pci_reset_notify(), but we expand the region
since we have several calls following each other.
Without this, ->reset_notify() may race with ->remove() calls, which can be
easily triggered in NVMe.
[bhelgaas: changelog, add pci_reset_notify() comment]
[bhelgaas: fold in fix from Dan Carpenter <dan.carpenter@oracle.com>:
http://lkml.kernel.org/r/20170701135323.x5vaj4e2wcs2mcro@mwanda]
Link: http://lkml.kernel.org/r/20170601111039.8913-2-hch@lst.de
Reported-by: Rakesh Pandit <rakesh@tuxera.com>
Tested-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 3b38e98e68df..f4587f6f8739 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4143,6 +4143,12 @@ static void pci_reset_notify(struct pci_dev *dev, bool prepare) { const struct pci_error_handlers *err_handler = dev->driver ? dev->driver->err_handler : NULL; + + /* + * dev->driver->err_handler->reset_notify() is protected against + * races with ->remove() by the device lock, which must be held by + * the caller. + */ if (err_handler && err_handler->reset_notify) err_handler->reset_notify(dev, prepare); } @@ -4278,11 +4284,13 @@ int pci_reset_function(struct pci_dev *dev) if (rc) return rc; + pci_dev_lock(dev); pci_dev_save_and_disable(dev); - rc = pci_dev_reset(dev, 0); + rc = __pci_dev_reset(dev, 0); pci_dev_restore(dev); + pci_dev_unlock(dev); return rc; } @@ -4302,16 +4310,14 @@ int pci_try_reset_function(struct pci_dev *dev) if (rc) return rc; - pci_dev_save_and_disable(dev); + if (!pci_dev_trylock(dev)) + return -EAGAIN; - if (pci_dev_trylock(dev)) { - rc = __pci_dev_reset(dev, 0); - pci_dev_unlock(dev); - } else - rc = -EAGAIN; + pci_dev_save_and_disable(dev); + rc = __pci_dev_reset(dev, 0); + pci_dev_unlock(dev); pci_dev_restore(dev); - return rc; } EXPORT_SYMBOL_GPL(pci_try_reset_function); @@ -4461,7 +4467,9 @@ static void pci_bus_save_and_disable(struct pci_bus *bus) struct pci_dev *dev; list_for_each_entry(dev, &bus->devices, bus_list) { + pci_dev_lock(dev); pci_dev_save_and_disable(dev); + pci_dev_unlock(dev); if (dev->subordinate) pci_bus_save_and_disable(dev->subordinate); } @@ -4476,7 +4484,9 @@ static void pci_bus_restore(struct pci_bus *bus) struct pci_dev *dev; list_for_each_entry(dev, &bus->devices, bus_list) { + pci_dev_lock(dev); pci_dev_restore(dev); + pci_dev_unlock(dev); if (dev->subordinate) pci_bus_restore(dev->subordinate); } |