linux-kernel - Re: [PATCH 4.19 144/187] selftests/bpf: skip verifier tests for unsupported program types

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Date:   Thu, 23 May 2019 10:27:54 +0000
From:   "Rantala, Tommi T. (Nokia - FI/Espoo)" <tommi.t.rantala@...ia.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
CC:     "daniel@...earbox.net" <daniel@...earbox.net>,
        "sashal@...nel.org" <sashal@...nel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "sdf@...gle.com" <sdf@...gle.com>
Subject: Re: [PATCH 4.19 144/187] selftests/bpf: skip verifier tests for
 unsupported program types

On Thu, 2019-04-04 at 10:48 +0200, Greg Kroah-Hartman wrote:
> 4.19-stable review patch.  If anyone has any objections, please let
> me know.
> 
> ------------------
> 
> [ Upstream commit 8184d44c9a577a2f1842ed6cc844bfd4a9981d8e ]
> 
> Use recently introduced bpf_probe_prog_type() to skip tests in the
> test_verifier() if bpf_verify_program() fails. The skipped test is
> indicated in the output.

Hi, this patch added in 4.19.34 causes test_verifier build failure, as
bpf_probe_prog_type() is not available:

gcc -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf
-I../../../../include/generated -DHAVE_GENHDR
-I../../../include    test_verifier.c /root/linux-
4.19.44/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread
-o /root/linux-4.19.44/tools/testing/selftests/bpf/test_verifier
test_verifier.c: In function ‘do_test_single’:
test_verifier.c:12775:22: warning: implicit declaration of function
‘bpf_probe_prog_type’; did you mean ‘bpf_program__set_type’? [-
Wimplicit-function-declaration]
  if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) {
                      ^~~~~~~~~~~~~~~~~~~
                      bpf_program__set_type
/usr/bin/ld: /tmp/ccEtyLhk.o: in function `do_test_single':
test_verifier.c:(.text+0xa19): undefined reference to
`bpf_probe_prog_type'
collect2: error: ld returned 1 exit status
make[1]: *** [../lib.mk:152: /root/linux-
4.19.44/tools/testing/selftests/bpf/test_verifier] Error 1


- Tommi

> Example:
> 
> ...
> 679/p bpf_get_stack return R0 within range SKIP (unsupported program
> type 5)
> 680/p ld_abs: invalid op 1 OK
> ...
> Summary: 863 PASSED, 165 SKIPPED, 3 FAILED
> 
> Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
>  tools/testing/selftests/bpf/test_verifier.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_verifier.c
> b/tools/testing/selftests/bpf/test_verifier.c
> index 9db5a7378f40..294fc18aba2a 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -32,6 +32,7 @@
>  #include <linux/if_ether.h>
>  
>  #include <bpf/bpf.h>
> +#include <bpf/libbpf.h>
>  
>  #ifdef HAVE_GENHDR
>  # include "autoconf.h"
> @@ -56,6 +57,7 @@
>  
>  #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
>  static bool unpriv_disabled = false;
> +static int skips;
>  
>  struct bpf_test {
>  	const char *descr;
> @@ -12770,6 +12772,11 @@ static void do_test_single(struct bpf_test
> *test, bool unpriv,
>  	fd_prog = bpf_verify_program(prog_type ? :
> BPF_PROG_TYPE_SOCKET_FILTER,
>  				     prog, prog_len, test->flags &
> F_LOAD_WITH_STRICT_ALIGNMENT,
>  				     "GPL", 0, bpf_vlog,
> sizeof(bpf_vlog), 1);
> +	if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) {
> +		printf("SKIP (unsupported program type %d)\n",
> prog_type);
> +		skips++;
> +		goto close_fds;
> +	}
>  
>  	expected_ret = unpriv && test->result_unpriv != UNDEF ?
>  		       test->result_unpriv : test->result;
> @@ -12905,7 +12912,7 @@ static void get_unpriv_disabled()
>  
>  static int do_test(bool unpriv, unsigned int from, unsigned int to)
>  {
> -	int i, passes = 0, errors = 0, skips = 0;
> +	int i, passes = 0, errors = 0;
>  
>  	for (i = from; i < to; i++) {
>  		struct bpf_test *test = &tests[i];