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Karl Mehltretter
39b975ff20
arm32 allmodconfig fails to build with gcc: drivers/mtd/chips/cfi_cmdset_0001.c:1883:1: error: the frame size of 1296 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] With MTD_MAP_BANK_WIDTH_32 a map_word is 32 bytes, and with KASAN_STACK every temporary gets its own redzoned slot. do_write_buffer() builds a map_word for each of the twelve commands it issues, and those temporaries dominate its frame. Issue the commands through a small noinline helper that takes the command as a plain value and builds the map_word in its own frame. The sequence of reads and writes to the chip is unchanged. The helper must not be inlined, and reusing one map_word local is not enough: clang cannot assume the callee does not observe the local, so it still returns each CMD() into a per-call-site temporary, and the frame grows (1760 -> 1824 bytes in cfi_intelext_writev(), into which clang inlines do_write_buffer()). Frame sizes with MTD_MAP_BANK_WIDTH_32 and KASAN_STACK: gcc 15.2 do_write_buffer() 1296 -> 520 clang 21 cfi_intelext_writev() 1760 -> 896 The helper itself takes 168 (gcc) / 160 (clang) bytes. Reported-by: Andy Shevchenko <[email protected]> Closes: https://lore.kernel.org/all/[email protected]/ Suggested-by: Miquel Raynal <[email protected]> Link: https://lore.kernel.org/all/[email protected]/ Assisted-by: LLM Signed-off-by: Karl Mehltretter <[email protected]> Signed-off-by: Miquel Raynal <[email protected]>