Re: BPF selftest failed to build

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Aug 23, 2024 at 10:50:29AM +0800, Shung-Hsi Yu wrote:
> On Thu, Aug 22, 2024 at 06:45:14PM GMT, Sherry Yang wrote:
> > Hi All,
> > 
> > We found BPF sefltest fail to build with following error:
> > 
> > 08-09 20:39:59 DBG: |output|: progs/test_global_func10.c:24:1: error: unknown type name '__failure'
> > 08-09 20:39:59 DBG: |output|: __failure __msg("invalid indirect access to stack")
> > 08-09 20:39:59 DBG: |output|: ^
> > 08-09 20:39:59 DBG: |output|: progs/test_global_func10.c:24:17: error: expected parameter declarator
> > 08-09 20:39:59 DBG: |output|: __failure __msg("invalid indirect access to stack")
> > 08-09 20:39:59 DBG: |output|:                 ^
> > 08-09 20:39:59 DBG: |output|: progs/test_global_func10.c:24:17: error: expected ')'
> > 08-09 20:39:59 DBG: |output|: progs/test_global_func10.c:24:16: note: to match this '('
> > 08-09 20:39:59 DBG: |output|: __failure __msg("invalid indirect access to stack")
> > 08-09 20:39:59 DBG: |output|:                ^
> > 08-09 20:39:59 DBG: |output|: progs/test_global_func10.c:24:52: error: expected ';' after top level declarator
> > 08-09 20:39:59 DBG: |output|: __failure __msg("invalid indirect access to stack")
> > 08-09 20:39:59 DBG: |output|:                                                    ^
> > 08-09 20:39:59 DBG: |output|:                                                    ;
> > 08-09 20:39:59 DBG: |output|: 4 errors generated.
> > 08-09 20:39:59 DBG: |output|: make: *** [Makefile:470: /root/oltf/work/linux-bpf-qa/tools/testing/selftests/bpf/test_global_func10.o] Error 1
> > 08-09 20:39:59 DBG: |output|: make: *** Waiting for unfinished jobs....
> > 
> > It happens from the commit e30bc19a9ee8("bpf: Allow reads from uninit
> > stack"). We did a further look, '__failure' is defined in
> > tools/testing/selftests/bpf/progs/bpf_misc.h, and was 1st introduced
> > in commit 537c3f66eac1("selftests/bpf: add generic BPF program
> > tester-loader") which is not backported to linux-5.15.y.
> > 
> > So we may need to revert the patch, or fix it.
> 
> To fix it I think we just need to drop the use of __failure and __msg in
> progs/test_global_func10.c, and update the "struct test_def tests[]"
> table in prog_tests/test_global_funcs.c with the new verifier rejection
> message.
> 
> On the other hand I believe commit 537c3f66eac1("selftests/bpf: add
> generic BPF program tester-loader") should be relatively easy to
> backport, just picking that commit up and resolving simple conflict in
> Makefile should be enough. It will also save a lot of future headaches
> like this one.

Please submit a patch like this and we will be glad to pick it up.

thanks,

greg k-h