[PATCH 0/3] PCI: endpoint: Clarify pci_epc_set_bar() lifetime rules

Koichiro Den
2026-01-31T13:37:07Z

Hi,

This patch series is a follow-up to a side discussion that started from
Niklas' comment at:
https://lore.kernel.org/all/aXtrW7viGZfMNZur@ryzen/

That discussion highlighted implicit ownership/lifetime assumptions in
the pci_epc_set_bar() interface: some EPC drivers keep a reference to
the struct pci_epf_bar passed in (and its optional submap array).
Mutating or freeing those objects after a successful pci_epc_set_bar()
can lead to use-after-free or other undefined or hard-to-debug behavior.

This series:
1) Makes BAR Match vs Address Match teardown in DesignWare EP explicit
by returning right after clearing a BAR-match inbound mapping.
2) Fixes pci-epf-test BAR subrange mapping to use a dedicated
pci_epf_bar instance and to free the allocated submap only after
restoring the default BAR mapping.
3) Documents pci_epc_set_bar() caller ownership and lifetime rules.

Base: controller/dwc branch, latest:
commit a24149881558 ("PCI: dwc: ep: Add comment explaining controller level
PTM access in multi PF setup")

Thanks,

Koichiro Den (3):
PCI: dwc: ep: Return after clearing BAR-match inbound mapping
PCI: endpoint: pci-epf-test: Use dedicated pci_epf_bar for subrange
mapping
PCI: endpoint: Document pci_epc_set_bar() caller ownership and
lifetime rules

Documentation/PCI/endpoint/pci-endpoint.rst | 22 +++++++++++++
.../pci/controller/dwc/pcie-designware-ep.c | 1 +
drivers/pci/endpoint/functions/pci-epf-test.c | 32 ++++++-------------
3 files changed, 33 insertions(+), 22 deletions(-)

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2.51.0