Re: [PATCH bpf-next] selftests/bpf: Fix building error when using userspace pt_regs

On 2021/12/15 9:20, Pu Lehui wrote:

On 2021/12/15 4:01, Daniel Borkmann wrote:

quoted

On 12/14/21 2:55 PM, Pu Lehui wrote:

quoted

When building bpf selftests on arm64, the following error will occur:

progs/loop2.c:20:7: error: incomplete definition of type 'struct
user_pt_regs'

Some archs, like arm64 and riscv, use userspace pt_regs in
bpf_tracing.h, which causes build failure when bpf prog use
macro in bpf_tracing.h. So let's use vmlinux.h directly.

Signed-off-by: Pu Lehui <pulehui@huawei.com>

Looks like this lets CI fail, did you run the selftests also with 
vmtest.sh to
double check?

https://github.com/kernel-patches/bpf/runs/4521708490?check_suite_focus=true 
:

[...]
#189 verif_scale_loop6:FAIL
libbpf: prog 'trace_virtqueue_add_sgs': BPF program load failed: 
Argument list too long
libbpf: prog 'trace_virtqueue_add_sgs': -- BEGIN PROG LOAD LOG --
R1 type=ctx expected=fp
BPF program is too large. Processed 1000001 insn
verification time 12250995 usec
stack depth 88
processed 1000001 insns (limit 1000000) max_states_per_insn 107 
total_states 21739 peak_states 2271 mark_read 6
-- END PROG LOAD LOG --
libbpf: failed to load program 'trace_virtqueue_add_sgs'
libbpf: failed to load object 'loop6.o'
scale_test:FAIL:expect_success unexpected error: -7 (errno 7)
Summary: 221/986 PASSED, 8 SKIPPED, 1 FAILED
[...]

Please take a look and fix in your patch, thanks!
.

Sorry for my negligence, I'll take a look and fix it.
.

It seems strange that verifier think the loop can execute up to u64_max 
while I just replace the header file.
This looks very similar to the previous llvm issue, 
https://github.com/iovisor/bcc/pull/3270, but I have no idea how to locate.

Back to arm64 bpf selftest compiling problem, we can use header file 
directory generated by "make headers_install" to fix it.

--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile

@@ -294,7 +294,8 @@ MENDIAN=$(if 

$(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)
  CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
  BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \
  	     -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) \
-	     -I$(abspath $(OUTPUT)/../usr/include)
+	     -I$(abspath $(OUTPUT)/../usr/include) \
+	     -I../../../../usr/include