Re: [PATCH v2] PCI: endpoint: pci-epf-test: Fix double free Oops

From: Krzysztof Wilczyński
Date: Thu Feb 20 2025 - 10:33:10 EST


Hello,

> Fixes an oops found while testing the stm32_pcie ep driver with handling
> of PERST# deassertion:
>
> During EP initialization, pci_epf_test_alloc_space allocates all BARs,
> which are further freed if epc_set_bar fails (for instance, due to
> no free inbound window).
>
> However, when pci_epc_set_bar fails, the error path:
> pci_epc_set_bar -> pci_epf_free_space
> does not reset epf_test->reg[bar].
>
> Then, if the host reboots, PERST# deassertion restarts the BAR allocation
> sequence with the same allocation failure (no free inbound window),
> creating a double free situation since epf_test->reg[bar] was deallocated
> and is still non-NULL.
>
> Make sure that pci_epf_alloc_space/pci_epf_free_space are symmetric
> by resetting epf_test->reg[bar] when memory is deallocated.

Applied to endpoint, thank you!

Krzysztof