On Tue, 1 Jul 2025 08:23:24 -0700 Nathan Chancellor nathan@kernel.org wrote:
commit a55bc4ffc06d8c965a7d6f0a01ed0ed41380df28 upstream.
After commit 6f110a5e4f99 ("Disable SLUB_TINY for build testing"), which causes CONFIG_KASAN to be enabled in allmodconfig again, arm64 allmodconfig builds with older versions of clang (15 through 17) show an instance of -Wframe-larger-than (which breaks the build with CONFIG_WERROR=y):
drivers/staging/rtl8723bs/core/rtw_security.c:1287:5: error: stack frame size (2208) exceeds limit (2048) in 'rtw_aes_decrypt' [-Werror,-Wframe-larger-than] 1287 | u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe) | ^
This comes from aes_decipher() being inlined in rtw_aes_decrypt(). Running the same build with CONFIG_FRAME_WARN=128 shows aes_cipher() also uses a decent amount of stack, just under the limit of 2048:
drivers/staging/rtl8723bs/core/rtw_security.c:864:19: warning: stack frame size (1952) exceeds limit (128) in 'aes_cipher' [-Wframe-larger-than] 864 | static signed int aes_cipher(u8 *key, uint hdrlen, | ^
...
The memset() calls are just initializing these buffers to zero, so use '= {}' instead, which is used all over the kernel and does the exact same thing as memset() without the fortify checks, which drops the stack usage of these functions by a few hundred kilobytes.
I suspect you mean bytes....
David
drivers/staging/rtl8723bs/core/rtw_security.c:864:19: warning: stack frame size (1584) exceeds limit (128) in 'aes_cipher' [-Wframe-larger-than] 864 | static signed int aes_cipher(u8 *key, uint hdrlen, | ^ drivers/staging/rtl8723bs/core/rtw_security.c:1271:5: warning: stack frame size (1456) exceeds limit (128) in 'rtw_aes_decrypt' [-Wframe-larger-than] 1271 | u32 rtw_aes_decrypt(struct adapter *padapter, u8 *precvframe) | ^