On Tue, Jul 9, 2024 at 8:19 PM Hao Peng <flyingpenghao@xxxxxxxxx> wrote: > > On Thu, Jun 13, 2024 at 11:02 AM Alexei Starovoitov > <alexei.starovoitov@xxxxxxxxx> wrote: > > > > On Wed, Jun 12, 2024 at 7:19 PM <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. > > > > > > kernel/bpf/verifier.c:21163:5: error: stack frame size (2392) exceeds > > > limit (2048) in 'bpf_check' [-Werror,-Wframe-larger-than] > > > int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, > > > __u32 uattr_size) > > > ^ > > > 632/2392 (26.42%) spills, 1760/2392 (73.58%) variables > > > so increase the limit for configurations that have KASAN or KCSAN enabled for not > > > breaking the majority of builds. > > > > > > Signed-off-by: Peng Hao <flyingpeng@xxxxxxxxxxx> > > > --- > > > kernel/bpf/Makefile | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile > > > index e497011261b8..07ed1e81aa62 100644 > > > --- a/kernel/bpf/Makefile > > > +++ b/kernel/bpf/Makefile > > > @@ -6,6 +6,12 @@ cflags-nogcse-$(CONFIG_X86)$(CONFIG_CC_IS_GCC) := -fno-gcse > > > endif > > > CFLAGS_core.o += -Wno-override-init $(cflags-nogcse-yy) > > > > > > +ifneq ($(CONFIG_FRAME_WARN),0) > > > +ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y) > > > +CFLAGS_verifier.o = -Wframe-larger-than=2392 > > > > that's very compiler specific. > > version +-1 will have different results. > > Please investigate what is causing the large stack size instead. > > pw-bot: cr > This increase in stack frame size only occurs when KASAN or KCSAN is > configured. KASAN or > KCSAN will cause the stack frame size to increase, and it will insert > additional code and data > structures to detect memory errors during compilation. These > additional checks will increase > the stack space requirements of the function. This generic statement about kasan is not helpful. Figure out which exact variables and what functions are causing this kasan behavior.
