PCI: Lock upstream bridge for pci_reset_function()

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Fix a long-standing locking gap for missing pci_cfg_access_lock() while
manipulating bridge reset registers and configuration during
pci_reset_bus_function().

If there is an upstream bridge, lock it before locking the device itself.
pci_dev_lock() calls pci_cfg_access_lock(), which blocks the writing of PCI
config space by user space.

Add lockdep assertion via pci_dev->cfg_access_lock to verify
pci_dev->block_cfg_access is set.

Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20240502165851.1948523-3-dave.jiang@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

...

This commit is contained in:

Dave Jiang 2024-05-02 09:57:31 -07:00 • committed by Bjorn Helgaas

parent 962f1e79e7

commit 7e89efc6e9

5 changed files with 27 additions and 0 deletions

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4

drivers/pci/access.c

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13

drivers/pci/pci.c

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3

drivers/pci/probe.c

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5

include/linux/lockdep.h

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2

include/linux/pci.h

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