Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 5 Jan 2021 10:25:34 +0100 | Subject | Re: [PATCH] ubsan: disable unsigned-integer-overflow sanitizer with clang |
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On Mon, Jan 4, 2021 at 11:33 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > On Wed, Dec 30, 2020 at 05:13:03PM +0100, Marco Elver wrote: > > On Wed, 30 Dec 2020 at 16:47, Arnd Bergmann <arnd@kernel.org> wrote: > > > > > > 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. > > This patch also fixes the failed BUILD_BUG issue in mm/mremap.c that you > sent a patch for [1], along with a couple of other issues I see such as:
I'm fairly sure I still saw that BUILD_BUG() even after I had applied this patch, I would guess that one just depends on inlining decisions that are influenced by all kinds of compiler options including -fsanitize=unsigned-integer-overflow, so it becomes less likely.
I'll revert my other patch in the randconfig tree to see if it comes back.
Arnd
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