Christian Bruel fe2329eff5 PCI: endpoint: pci-epf-test: Fix double free that causes kernel to oops
[ Upstream commit 934e9d137d ]

Fix a kernel oops found while testing the stm32_pcie Endpoint 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 clear the previous assignment to epf_test->reg[bar].

Then, if the host reboots, the 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.

Thus, make sure that pci_epf_alloc_space() and pci_epf_free_space()
invocations are symmetric, and as such, set epf_test->reg[bar] to NULL
when memory is freed.

Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
Link: https://lore.kernel.org/r/20250124123043.96112-1-christian.bruel@foss.st.com
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29 11:02:25 +02:00
2025-05-29 11:02:23 +02:00
2025-05-29 11:02:07 +02:00
2025-05-29 11:02:23 +02:00
2025-05-22 14:29:54 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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