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The bitfield dma_inuse is allocated of size dma_requests bits, thus a valid bit address is from 0 to (dma_requests - 1). When find_first_zero_bit() fails, it returns dma_requests as invalid address. Using such address for the following set_bit() is incorrect and, if dma_requests is a multiple of BITS_PER_LONG, it will cause a buffer overflow. Currently this driver is only used in DT stm32h743.dtsi where a safe value dma_requests=16 is not triggering the buffer overflow. Fixed by checking the return value of find_first_zero_bit() _before_ using it. Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.