(cc Arnd, Nathan) On Fri, 12 Jul 2024 at 13:37, <flyingpenghao@xxxxxxxxx> wrote: > > From: Peng Hao <flyingpeng@xxxxxxxxxxx> > > When building kernel with clang, which will typically > have sanitizers enabled, there is a warning about a large stack frame. > > crypto/ecc.c:1129:13: error: stack frame size (2136) exceeds limit (2048) in 'ecc_point_double_jacobian' [-Werror,-Wframe-larger-than] > static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1, > ^ > > Since many arrays are defined in ecc_point_double_jacobian, they occupy a > lot of stack space, but are difficult to adjust. just increase the limit > for configurations that have KASAN or KCSAN enabled. > > Signed-off-by: Peng Hao <flyingpeng@xxxxxxxxxxx> > --- > crypto/Makefile | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/crypto/Makefile b/crypto/Makefile > index edbbaa3ffef5..ab7bebaa7218 100644 > --- a/crypto/Makefile > +++ b/crypto/Makefile > @@ -190,6 +190,12 @@ obj-$(CONFIG_CRYPTO_ECC) += ecc.o > obj-$(CONFIG_CRYPTO_ESSIV) += essiv.o > obj-$(CONFIG_CRYPTO_CURVE25519) += curve25519-generic.o > > +ifneq ($(CONFIG_FRAME_WARN),0) > +ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y) > +CFLAGS_ecc.o = -Wframe-larger-than=2776 > +endif > +endif > + I don't think this is an acceptable workaround - this applies to all functions in the file, which call into each other as well. It would be better if we could figure out why the stack blows up like this on clang, which could be related to inlining behavior or other compiler heuristics that prevent stack allocations from being reused. Arnd, Nathan: any insights?
