Re: [PATCH bpf-next] selftests/bpf: Fix d_path test

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Aug 31, 2023 at 01:46:09PM +0200, Daniel Borkmann wrote:
> On 8/31/23 1:00 PM, Jiri Olsa wrote:
> > Recent commit [1] broken d_path test, because now filp_close is not called
> > directly from sys_close, but eventually later when the file is finally
> > released.
> > 
> > As suggested by Hou Tao we don't need to re-hook the bpf program, but just
> > instead we can use sys_close_range to trigger filp_close synchronously.
> > 
> > [1] 021a160abf62 ("fs: use __fput_sync in close(2)")
> > Suggested-by: Hou Tao <houtao@huaweicloud.com>
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >   tools/testing/selftests/bpf/prog_tests/d_path.c | 8 +++++++-
> >   1 file changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/d_path.c b/tools/testing/selftests/bpf/prog_tests/d_path.c
> > index 911345c526e6..81e34a4a05d1 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/d_path.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/d_path.c
> > @@ -90,7 +90,11 @@ static int trigger_fstat_events(pid_t pid)
> >   	fstat(indicatorfd, &fileStat);
> >   out_close:
> > -	/* triggers filp_close */
> > +	/* sys_close no longer triggers filp_close, but we can
> > +	 * call sys_close_range instead which still does
> > +	 */
> > +#define close(fd) close_range(fd, fd, 0)
> > +
> 
> The BPF CI selftest build says:
> 
>     [...]
>     TEST-OBJ [test_progs] lookup_key.test.o
>     TEST-OBJ [test_progs] migrate_reuseport.test.o
>     TEST-OBJ [test_progs] user_ringbuf.test.o
>   /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/d_path.c: In function ‘trigger_fstat_events’:
>   /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/d_path.c:96:19: error: implicit declaration of function ‘close_range’ [-Werror=implicit-function-declaration]
>      96 | #define close(fd) close_range(fd, fd, 0)
>         |                   ^~~~~~~~~~~
>   /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/d_path.c:98:2: note: in expansion of macro ‘close’
>      98 |  close(pipefd[0]);
>         |  ^~~~~
>     TEST-OBJ [test_progs] task_pt_regs.test.o
>     [...]
> 
> Perhaps #include <linux/close_range.h> missing ?

yes, will send v2

thanks,
jirka

> 
> >   	close(pipefd[0]);
> >   	close(pipefd[1]);
> >   	close(sockfd);
> > @@ -98,6 +102,8 @@ static int trigger_fstat_events(pid_t pid)
> >   	close(devfd);
> >   	close(localfd);
> >   	close(indicatorfd);
> > +
> > +#undef close
> >   	return ret;
> >   }
> > 
>