Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] ubsan: disable unsigned-integer-overflow sanitizer with clang | Date | Wed, 30 Dec 2020 16:47:35 +0100 |
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From: Arnd Bergmann <arnd@arndb.de>
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.
The one in blake2b immediately overflows the 8KB stack area on 32-bit architectures, so better ensure this never happens by making this option gcc-only.
Fixes: d0a3ac549f38 ("ubsan: enable for all*config builds") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- lib/Kconfig.ubsan | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 8b635fd75fe4..e23873282ba7 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -122,6 +122,8 @@ config UBSAN_SIGNED_OVERFLOW config UBSAN_UNSIGNED_OVERFLOW bool "Perform checking for unsigned arithmetic overflow" + # clang hugely expands stack usage with -fsanitize=object-size + depends on !CC_IS_CLANG depends on $(cc-option,-fsanitize=unsigned-integer-overflow) help This option enables -fsanitize=unsigned-integer-overflow which checks -- 2.29.2
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