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s390/pci: fix leak of PCI device structure

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In commit 05bc1be6db ("s390/pci: create zPCI bus") we removed the
pci_dev_put() call matching the earlier pci_get_slot() done as part of
__zpci_event_availability(). This was based on the wrong understanding
that the device_put() done as part of pci_destroy_device() would counter
the pci_get_slot() when it only counters the initial reference. This
same understanding and existing bad example also lead to not doing
a pci_dev_put() in zpci_remove_device().

Since releasing the PCI devices, unlike releasing the PCI slot, does not
print any debug message for testing I added one in pci_release_dev().
This revealed that we are indeed leaking the PCI device on PCI
hotunplug. Further testing also revealed another missing pci_dev_put() in
disable_slot().

Fix this by adding the missing pci_dev_put() in disable_slot() and fix
zpci_remove_device() with the correct pci_dev_put() calls. Also instead
of calling pci_get_slot() in __zpci_event_availability() to determine if
a PCI device is registered and then doing the same again in
zpci_remove_device() do this once in zpci_remove_device() which makes
sure that the pdev in __zpci_event_availability() is only used for the
result of pci_scan_single_device() which does not need a reference count
decremnt as its ownership goes to the PCI bus.

Also move the check if zdev->zbus->bus is set into zpci_remove_device()
since it may be that we're removing a device with devfn != 0 which never
had a PCI bus. So we can still set the pdev->error_state to indicate
that the device is not usable anymore, add a flag to set the error state.

Fixes: 05bc1be6db ("s390/pci: create zPCI bus")
Cc: <stable@vger.kernel.org> # 5.8+: e1bff843cd s390/pci: remove superfluous zdev->zbus check
Cc: <stable@vger.kernel.org> # 5.8+: ba764dd703 s390/pci: refactor zpci_create_device()
Cc: <stable@vger.kernel.org> # 5.8+
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Niklas Schnelle 2021-03-10 13:46:26 +01:00 committed by Heiko Carstens
parent d54cb7d548
commit 0b13525c20
4 changed files with 33 additions and 18 deletions
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2
arch/s390/include/asm/pci.h
View file

@ -202,7 +202,7 @@ extern unsigned int s390_pci_no_rid;
----------------------------------------------------------------------------- */
/* Base stuff */
int zpci_create_device(u32 fid, u32 fh, enum zpci_state state);
void zpci_remove_device(struct zpci_dev *zdev);
void zpci_remove_device(struct zpci_dev *zdev, bool set_error);
int zpci_enable_device(struct zpci_dev *);
int zpci_disable_device(struct zpci_dev *);
int zpci_register_ioat(struct zpci_dev *, u8, u64, u64, u64);

28
arch/s390/pci/pci.c
View file

@ -682,16 +682,36 @@ int zpci_disable_device(struct zpci_dev *zdev)
}
EXPORT_SYMBOL_GPL(zpci_disable_device);
void zpci_remove_device(struct zpci_dev *zdev)
/* zpci_remove_device - Removes the given zdev from the PCI core
* @zdev: the zdev to be removed from the PCI core
* @set_error: if true the device's error state is set to permanent failure
*
* Sets a zPCI device to a configured but offline state; the zPCI
* device is still accessible through its hotplug slot and the zPCI
* API but is removed from the common code PCI bus, making it
* no longer available to drivers.
*/
void zpci_remove_device(struct zpci_dev *zdev, bool set_error)
{
struct zpci_bus *zbus = zdev->zbus;
struct pci_dev *pdev;
if (!zdev->zbus->bus)
return;
pdev = pci_get_slot(zbus->bus, zdev->devfn);
if (pdev) {
if (pdev->is_virtfn)
return zpci_iov_remove_virtfn(pdev, zdev->vfn);
if (set_error)
pdev->error_state = pci_channel_io_perm_failure;
if (pdev->is_virtfn) {
zpci_iov_remove_virtfn(pdev, zdev->vfn);
/* balance pci_get_slot */
pci_dev_put(pdev);
return;
}
pci_stop_and_remove_bus_device_locked(pdev);
/* balance pci_get_slot */
pci_dev_put(pdev);
}
}
@ -765,7 +785,7 @@ void zpci_release_device(struct kref *kref)
struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref);
if (zdev->zbus->bus)
zpci_remove_device(zdev);
zpci_remove_device(zdev, false);
switch (zdev->state) {
case ZPCI_FN_STATE_ONLINE:

18
arch/s390/pci/pci_event.c
View file

@ -76,13 +76,10 @@ void zpci_event_error(void *data)
static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
{
struct zpci_dev *zdev = get_zdev_by_fid(ccdf->fid);
struct pci_dev *pdev = NULL;
enum zpci_state state;
struct pci_dev *pdev;
int ret;
if (zdev && zdev->zbus->bus)
pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
zpci_err("avail CCDF:\n");
zpci_err_hex(ccdf, sizeof(*ccdf));
@ -124,8 +121,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
case 0x0303: /* Deconfiguration requested */
if (!zdev)
break;
if (pdev)
zpci_remove_device(zdev);
zpci_remove_device(zdev, false);
ret = zpci_disable_device(zdev);
if (ret)
@ -140,12 +136,10 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
case 0x0304: /* Configured -> Standby|Reserved */
if (!zdev)
break;
if (pdev) {
/* Give the driver a hint that the function is
* already unusable. */
pdev->error_state = pci_channel_io_perm_failure;
zpci_remove_device(zdev);
}
/* Give the driver a hint that the function is
* already unusable.
*/
zpci_remove_device(zdev, true);
zdev->fh = ccdf->fh;
zpci_disable_device(zdev);

3
drivers/pci/hotplug/s390_pci_hpc.c
View file

@ -93,8 +93,9 @@ static int disable_slot(struct hotplug_slot *hotplug_slot)
pci_dev_put(pdev);
return -EBUSY;
}
pci_dev_put(pdev);
zpci_remove_device(zdev);
zpci_remove_device(zdev, false);
rc = zpci_disable_device(zdev);
if (rc)