ALLOC_CACHE_ALIGN_BUFFER was called here in a way to alloc in stack a possible huge quantity of memory depending on data transer size.
Es: loading kernel 8MB from eMMC we have Transfer size: 0x800000 Block size: 0x200 Transfer blocks: 0x4000 struct size: 0x10 Stack allocation: ((0x200 / 8) + 1) * 0x10 = 0x8010 (~32KB)
Since this allocation is done on stack, there is no current way to get an error on stack memory limit exceeded, overlapping heap space on environments with very strict stack + heap limits like TPL or SPL (where malloc size can be 16KB). Results are silent corruptions of heap on mmc transfer and random errors or CPU hang.
Using malloc_cache_aligned() we will alloc slightly bigger buffers but we do have evidence about memory allocation failure allowing developer to recognize the issue and take actions.
Signed-off-by: Alberto Panizzo alberto@amarulasolutions.com
drivers/mmc/dw_mmc.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-)
Reviewed-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com