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9dedabe95b
Commit8cc3bad9d9("spi: Remove unneded check for orig_nents") introduced a regression: unmapped data could now be passed to the DMA APIs, resulting in null pointer dereferences. Commit9f788ba457("spi: Don't mark message DMA mapped when no transfer in it is") and commitda560097c0("spi: Check if transfer is mapped before calling DMA sync APIs") addressed the problem, but only partially. Unidirectional transactions will still result in null pointer dereference. To prevent that from happening, assign a dummy scatterlist when no data is mapped, so that the DMA API can be called and not result in a null pointer dereference. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reported-by: Neil Armstrong <neil.armstrong@linaro.org> Closes: https://lore.kernel.org/r/8ae675b5-fcf9-4c9b-b06a-4462f70e1322@linaro.org Reported-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> Closes: https://lore.kernel.org/all/d3679496-2e4e-4a7c-97ed-f193bd53af1d@notapiano Closes: https://lore.kernel.org/all/4748499f-789c-45a8-b50a-2dd09f4bac8c@notapiano Fixes:8cc3bad9d9("spi: Remove unneded check for orig_nents") Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> [nfraprado: wrote the commit message] Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> Link: https://msgid.link/r/20240529-dma-oops-dummy-v1-1-bb43aacfb11b@collabora.com Signed-off-by: Mark Brown <broonie@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
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.