From: Arnd Bergmann <arnd@xxxxxxxx> Subject: ubsan: disable unsigned-overflow check for i386 Building ubsan kernels even for compile-testing introduced these warnings in my randconfig environment: crypto/blake2b_generic.c:98:13: error: stack frame size of 9636 bytes in function 'blake2b_compress' [-Werror,-Wframe-larger-than=] static void blake2b_compress(struct blake2b_state *S, crypto/sha512_generic.c:151:13: error: stack frame size of 1292 bytes in function 'sha512_generic_block_fn' [-Werror,-Wframe-larger-than=] static void sha512_generic_block_fn(struct sha512_state *sst, u8 const *src, lib/crypto/curve25519-fiat32.c:312:22: error: stack frame size of 2180 bytes in function 'fe_mul_impl' [-Werror,-Wframe-larger-than=] static noinline void fe_mul_impl(u32 out[10], const u32 in1[10], const u32 in2[10]) lib/crypto/curve25519-fiat32.c:444:22: error: stack frame size of 1588 bytes in function 'fe_sqr_impl' [-Werror,-Wframe-larger-than=] static noinline void fe_sqr_impl(u32 out[10], const u32 in1[10]) Further testing showed that this is caused by -fsanitize=unsigned-integer-overflow, but is isolated to the 32-bit x86 architecture. The one in blake2b immediately overflows the 8KB stack area architectures, so better ensure this never happens by disabling the option for 32-bit x86. Link: https://lkml.kernel.org/r/20210112202922.2454435-1-arnd@xxxxxxxxxx Link: https://lore.kernel.org/lkml/20201230154749.746641-1-arnd@xxxxxxxxxx/ Fixes: d0a3ac549f38 ("ubsan: enable for all*config builds") Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: George Popescu <georgepope@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/Kconfig.ubsan | 1 + 1 file changed, 1 insertion(+) --- a/lib/Kconfig.ubsan~ubsan-disable-unsigned-overflow-check-for-i386 +++ a/lib/Kconfig.ubsan @@ -123,6 +123,7 @@ config UBSAN_SIGNED_OVERFLOW config UBSAN_UNSIGNED_OVERFLOW bool "Perform checking for unsigned arithmetic overflow" depends on $(cc-option,-fsanitize=unsigned-integer-overflow) + depends on !X86_32 # avoid excessive stack usage on x86-32/clang help This option enables -fsanitize=unsigned-integer-overflow which checks for overflow of any arithmetic operations with unsigned integers. This _
