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38c8d02501
The code to lookup the scatter gather table entry assumed that it was
possible to use sg_virt() in order to lookup the DMA address in a mapped
scatter gather table. However, this assumption is incorrect as the DMA
mapping code may merge multiple entries into one. In that case, the DMA
address space may have e.g. two consecutive pages which is correctly
represented by the scatter gather list entry, however the virtual
addresses for these two pages may differ and the relationship cannot be
resolved anymore.
Avoid this problem entirely by working with the offset into the mapped
area instead of using virtual addresses. With that we only use the DMA
length and DMA address from the scatter gather list entries. The
underlying DMA/IOMMU code is therefore free to merge two entries into
one even if the virtual addresses space for the area is not continuous.
Fixes: 90db507552 ("wifi: iwlwifi: use already mapped data when TXing an AMSDU")
Reported-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Closes: https://lore.kernel.org/r/ZrNRoEbdkxkKFMBi@debian.local
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240812110640.460514-1-benjamin@sipsolutions.net
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.