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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
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@@ -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);