tools/bpf/bpftool/skeleton: replace bpf_probe_read_kernel with...

tools/bpf/bpftool/skeleton: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm

bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.

Link: https://lkml.kernel.org/r/20211120112738.45980-7-laoar.shao@gmail.comSigned-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/bpf/bpftool/skeleton/pid_iter.bpf.c

@@ -71,7 +71,7 @@ int iter(struct bpf_iter__task_file *ctx)
 
 	e.pid = task->tgid;
 	e.id = get_obj_id(file->private_data, obj_type);
-	bpf_probe_read_kernel(&e.comm, sizeof(e.comm),
+	bpf_probe_read_kernel_str(&e.comm, sizeof(e.comm),
 				  task->group_leader->comm);
 	bpf_seq_write(ctx->meta->seq, &e, sizeof(e));