[PATCH bpf-next] selftests/bpf: Fix test_attach_probe

[PATCH bpf-next] selftests/bpf: Fix test_attach_probe

[Alexei Starovoitov]

Fix two issues in test_attach_probe:
1. it was not able to parse /proc/self/maps beyond the first line,
   since %s means parse string until white space.
2. offset has to be accounted for otherwise uprobed address is incorrect.

Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/testing/selftests/bpf/prog_tests/attach_probe.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
index 5ed90ede2f1d..a0ee87c8e1ea 100644
--- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
+++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
@@ -3,7 +3,7 @@
 #include "test_attach_probe.skel.h"
 
 ssize_t get_base_addr() {
-	size_t start;
+	size_t start, offset;
 	char buf[256];
 	FILE *f;
 
@@ -11,10 +11,11 @@ ssize_t get_base_addr() {
 	if (!f)
 		return -errno;
 
-	while (fscanf(f, "%zx-%*x %s %*s\n", &start, buf) == 2) {
+	while (fscanf(f, "%zx-%*x %s %zx %*[^\n]\n",
+		      &start, buf, &offset) == 3) {
 		if (strcmp(buf, "r-xp") == 0) {
 			fclose(f);
-			return start;
+			return start - offset;
 		}
 	}
 
-- 
2.23.0

Re: [PATCH bpf-next] selftests/bpf: Fix test_attach_probe

[Yonghong Song]

On 12/18/19 6:04 PM, Alexei Starovoitov wrote:
> Fix two issues in test_attach_probe:
> 1. it was not able to parse /proc/self/maps beyond the first line,
>     since %s means parse string until white space.
> 2. offset has to be accounted for otherwise uprobed address is incorrect.
> 
> Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Acked-by: Yonghong Song <yhs@fb.com>

Re: [PATCH bpf-next] selftests/bpf: Fix test_attach_probe

[Andrii Nakryiko]

On Wed, Dec 18, 2019 at 6:04 PM Alexei Starovoitov <ast@kernel.org> wrote:
>
> Fix two issues in test_attach_probe:
> 1. it was not able to parse /proc/self/maps beyond the first line,
>    since %s means parse string until white space.
> 2. offset has to be accounted for otherwise uprobed address is incorrect.
>
> Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---

Thanks for fixing!

Acked-by: Andrii Nakryiko <andriin@fb.com>

>  tools/testing/selftests/bpf/prog_tests/attach_probe.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> index 5ed90ede2f1d..a0ee87c8e1ea 100644
> --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> @@ -3,7 +3,7 @@
>  #include "test_attach_probe.skel.h"
>
>  ssize_t get_base_addr() {
> -       size_t start;
> +       size_t start, offset;
>         char buf[256];
>         FILE *f;
>
> @@ -11,10 +11,11 @@ ssize_t get_base_addr() {
>         if (!f)
>                 return -errno;
>
> -       while (fscanf(f, "%zx-%*x %s %*s\n", &start, buf) == 2) {
> +       while (fscanf(f, "%zx-%*x %s %zx %*[^\n]\n",

never new [^<chars>] is possible, very nice!

> +                     &start, buf, &offset) == 3) {
>                 if (strcmp(buf, "r-xp") == 0) {
>                         fclose(f);
> -                       return start;
> +                       return start - offset;
>                 }
>         }
>
> --
> 2.23.0
>

Re: [PATCH bpf-next] selftests/bpf: Fix test_attach_probe

[Daniel Borkmann]

On Wed, Dec 18, 2019 at 06:04:42PM -0800, Alexei Starovoitov wrote:
> Fix two issues in test_attach_probe:
> 1. it was not able to parse /proc/self/maps beyond the first line,
>    since %s means parse string until white space.
> 2. offset has to be accounted for otherwise uprobed address is incorrect.
> 
> Fixes: 1e8611bbdfc9 ("selftests/bpf: add kprobe/uprobe selftests")
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Applied, thanks!