Re: [PATCH] perf record: handle death by SIGTERM

[David Ahern <dsahern@gmail.com>]

On 5/7/13 12:29 AM, Ingo Molnar wrote:
>
> * Stephane Eranian <eranian@google.com> wrote:
>
>> This is a good fix. I have run into this infinite loop in perf report
>> many times.
>
> Hm, perf record should really not assume much about the perf.data and
> should avoid infinite loops ...
>
> So while making perf.data more consistent on SIGTERM is a nice fix, perf
> report should be fixed as well to detect loops and such.
>
> Thanks,
>
> 	Ingo
>

This seems to do the trick:

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 326068a..e82646f 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2802,6 +2802,17 @@ int perf_session__read_header(struct perf_session 
*session, int fd)
     if (perf_file_header__read(&f_header, header, fd) < 0)
         return -EINVAL;

+   /*
+    * sanity check that perf.data was written cleanly: data size
+    * is initialized to 0 and updated only if the on_exit function
+    * is run. If data size is still 0 then the file cannot be
+    * processed.
+    */
+   if (f_header.data.size == 0) {
+       pr_err("data size is 0. Was record properly terminated?\n");
+       return -1;
+   }
+
     nr_attrs = f_header.attrs.size / f_header.attr_size;
     lseek(fd, f_header.attrs.offset, SEEK_SET);