From: Toke Høiland-Jørgensen toke@redhat.com
[ Upstream commit 450278977acbf494a20367c22fbb38729772d1fc ]
It seems Clang can in some cases turn on stack protection by default, which doesn't work with BPF. This was reported once before[0], but it seems the flag to explicitly turn off the stack protector wasn't added to the Makefile, so do that now.
The symptom of this is compile errors like the following:
error: <unknown>:0:0: in function bpf_prog1 i32 (%struct.__sk_buff*): A call to built-in function '__stack_chk_fail' is not supported.
[0] https://www.spinics.net/lists/netdev/msg556400.html
Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com Signed-off-by: Alexei Starovoitov ast@kernel.org Link: https://lore.kernel.org/bpf/20191216103819.359535-1-toke@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- samples/bpf/Makefile | 1 + 1 file changed, 1 insertion(+)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index e7ad48c605e0f..6d1df7117e117 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -219,6 +219,7 @@ BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \ readelf -S ./llvm_btf_verify.o | grep BTF; \ /bin/rm -f ./llvm_btf_verify.o)
+BPF_EXTRA_CFLAGS += -fno-stack-protector ifneq ($(BTF_LLVM_PROBE),) EXTRA_CFLAGS += -g else