Re: [PATCH] selftests: breakpoints: Fix wrong argument of ptrace() when single step

[Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>]

On 02/04/2021 02:30 AM, Shuah Khan wrote:
> On 2/3/21 1:39 AM, Tiezhu Yang wrote:
> > According to the error message, the first argument of ptrace() should be
> > PTRACE_SINGLESTEP instead of PTRACE_CONT when ptrace single step.
> >
> > Fixes: f43365ee17f8 ("selftests: arm64: add test for 
> > unaligned/inexact watchpoint handling")
> > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > ---
> >   tools/testing/selftests/breakpoints/breakpoint_test_arm64.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git 
> > a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c 
> > b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
> > index ad41ea6..2f4d4d6 100644
> > --- a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
> > +++ b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
> > @@ -143,7 +143,7 @@ static bool run_test(int wr_size, int wp_size, 
> > int wr, int wp)
> >       if (!set_watchpoint(pid, wp_size, wp))
> >           return false;
> >   -    if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
> > +    if (ptrace(PTRACE_SINGLESTEP, pid, NULL, NULL) < 0) {
> >           ksft_print_msg(
> >               "ptrace(PTRACE_SINGLESTEP) failed: %s\n",
> >               strerror(errno));
>
> Right before this it does a set_watchpoint(). PTRACE_CONT is what
> makes sense to me. Error might be the one that is incorrect here?

What do you think the following change? If it is OK, I will send v2 soon.

diff --git a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c 
b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
index ad41ea6..e704181 100644
--- a/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
+++ b/tools/testing/selftests/breakpoints/breakpoint_test_arm64.c
@@ -145,7 +145,7 @@ static bool run_test(int wr_size, int wp_size, int 
wr, int wp)

        if (ptrace(PTRACE_CONT, pid, NULL, NULL) < 0) {
                ksft_print_msg(
-                       "ptrace(PTRACE_SINGLESTEP) failed: %s\n",
+                       "ptrace(PTRACE_CONT) failed: %s\n",
                        strerror(errno));
                return false;
        }
@@ -159,7 +159,7 @@ static bool run_test(int wr_size, int wp_size, int 
wr, int wp)
        }
        alarm(0);
        if (WIFEXITED(status)) {
-               ksft_print_msg("child did not single-step\n");
+               ksft_print_msg("child exited prematurely\n");
                return false;
        }
        if (!WIFSTOPPED(status)) {

Thanks,
Tiezhu

> thanks,
> -- Shuah