With KASAN enabled, the typecheck macro leads to some serious stack memory, as seen in the rt2xxx drivers:
drivers/net/wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_init_registers': drivers/net/wireless/ralink/rt2x00/rt2800lib.c:5068:1: error: the frame size of 23768 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] drivers/net/wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_config_txpower_rt3593.isra.1': drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4126:1: error: the frame size of 14184 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] drivers/net/wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_config_channel_rf3053.isra.5': drivers/net/wireless/ralink/rt2x00/rt2800lib.c:2585:1: error: the frame size of 7632 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
If we express the macro in a way that avoids the local variables, this goes away and the stacks are comparable to building without KASAN.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- include/linux/typecheck.h | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/include/linux/typecheck.h b/include/linux/typecheck.h index eb5b74a575be..adb1579fa5f0 100644 --- a/include/linux/typecheck.h +++ b/include/linux/typecheck.h @@ -5,12 +5,7 @@ * Check at compile time that something is of a particular type. * Always evaluates to 1 so you may use it easily in comparisons. */ -#define typecheck(type,x) \ -({ type __dummy; \ - typeof(x) __dummy2; \ - (void)(&__dummy == &__dummy2); \ - 1; \ -}) +#define typecheck(type,x) ({(void)((typeof(type) *)NULL == (typeof(x) *)NULL); 1;})
/* * Check at compile time that 'function' is a certain type, or is a pointer