| Message ID | 1450820691-27588-1-git-send-email-ddaney.cavm@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Tue, Dec 22, 2015 at 01:44:51PM -0800, David Daney wrote: > From: David Daney <david.daney@cavium.com> > > The aer_inject module, when active, replaces the pci_ops structure of > the bus so that it can intercept config space accesses. If the config > space access needs to be forwarded to the original pci_ops, we must > restore the bus's original ops, as the read()/write() functions may > require use of the data in the pci_ops structure. An example of such > functions are the pci_generic_config*() functions in > drivers/pci/access.c. A failure to call these with a valid bus->ops > results in dereferencing an invalid bus->ops->map_bus pointer and > subsequent OOPs and system crash. > > So, do as suggested above. When calling to the original > read()/write() functions, temporarily switch back to the original > pci_ops. This is safe to do as the pci_lock must already be held, and > thus no other users of the bus->ops are possible. > > Signed-off-by: David Daney <david.daney@cavium.com> Applied to pci/aer for v4.6, thanks, David! > --- > drivers/pci/pcie/aer/aer_inject.c | 30 ++++++++++++++++++++++++++++-- > 1 file changed, 28 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c > index 182224a..2d60e0e 100644 > --- a/drivers/pci/pcie/aer/aer_inject.c > +++ b/drivers/pci/pcie/aer/aer_inject.c > @@ -188,7 +188,9 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where, > struct aer_error *err; > unsigned long flags; > struct pci_ops *ops; > + struct pci_ops *my_ops; > int domain; > + int rv; > > spin_lock_irqsave(&inject_lock, flags); > if (size != sizeof(u32)) > @@ -208,8 +210,19 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where, > } > out: > ops = __find_pci_bus_ops(bus); > + /* > + * pci_lock must already be held, so we can directly > + * manipulate bus->ops. Many config access functions, > + * including pci_generic_config_read() require the original > + * bus->ops be installed to function, so temporarily put them > + * back. > + */ > + my_ops = bus->ops; > + bus->ops = ops; > + rv = ops->read(bus, devfn, where, size, val); > + bus->ops = my_ops; > spin_unlock_irqrestore(&inject_lock, flags); > - return ops->read(bus, devfn, where, size, val); > + return rv; > } > > static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, > @@ -220,7 +233,9 @@ static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, > unsigned long flags; > int rw1cs; > struct pci_ops *ops; > + struct pci_ops *my_ops; > int domain; > + int rv; > > spin_lock_irqsave(&inject_lock, flags); > if (size != sizeof(u32)) > @@ -243,8 +258,19 @@ static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, > } > out: > ops = __find_pci_bus_ops(bus); > + /* > + * pci_lock must already be held, so we can directly > + * manipulate bus->ops. Many config access functions, > + * including pci_generic_config_write() require the original > + * bus->ops be installed to function, so temporarily put them > + * back. > + */ > + my_ops = bus->ops; > + bus->ops = ops; > + rv = ops->write(bus, devfn, where, size, val); > + bus->ops = my_ops; > spin_unlock_irqrestore(&inject_lock, flags); > - return ops->write(bus, devfn, where, size, val); > + return rv; > } > > static struct pci_ops pci_ops_aer = { > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c index 182224a..2d60e0e 100644 --- a/drivers/pci/pcie/aer/aer_inject.c +++ b/drivers/pci/pcie/aer/aer_inject.c @@ -188,7 +188,9 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where, struct aer_error *err; unsigned long flags; struct pci_ops *ops; + struct pci_ops *my_ops; int domain; + int rv; spin_lock_irqsave(&inject_lock, flags); if (size != sizeof(u32)) @@ -208,8 +210,19 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where, } out: ops = __find_pci_bus_ops(bus); + /* + * pci_lock must already be held, so we can directly + * manipulate bus->ops. Many config access functions, + * including pci_generic_config_read() require the original + * bus->ops be installed to function, so temporarily put them + * back. + */ + my_ops = bus->ops; + bus->ops = ops; + rv = ops->read(bus, devfn, where, size, val); + bus->ops = my_ops; spin_unlock_irqrestore(&inject_lock, flags); - return ops->read(bus, devfn, where, size, val); + return rv; } static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, @@ -220,7 +233,9 @@ static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, unsigned long flags; int rw1cs; struct pci_ops *ops; + struct pci_ops *my_ops; int domain; + int rv; spin_lock_irqsave(&inject_lock, flags); if (size != sizeof(u32)) @@ -243,8 +258,19 @@ static int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, } out: ops = __find_pci_bus_ops(bus); + /* + * pci_lock must already be held, so we can directly + * manipulate bus->ops. Many config access functions, + * including pci_generic_config_write() require the original + * bus->ops be installed to function, so temporarily put them + * back. + */ + my_ops = bus->ops; + bus->ops = ops; + rv = ops->write(bus, devfn, where, size, val); + bus->ops = my_ops; spin_unlock_irqrestore(&inject_lock, flags); - return ops->write(bus, devfn, where, size, val); + return rv; } static struct pci_ops pci_ops_aer = {