ptrace: renumber PTRACE_EVENT_STOP so that future new options and events can match

Denys Vlasenko · torvalds · commit 5cdf389aee90 · 2012-03-23T16:58:41.000-07:00
PTRACE_EVENT_foo and PTRACE_O_TRACEfoo used to match.

New PTRACE_EVENT_STOP is the first event which has no corresponding
PTRACE_O_TRACE option.  If we will ever want to add another such option,
its PTRACE_EVENT's value will collide with PTRACE_EVENT_STOP's value.

This patch changes PTRACE_EVENT_STOP value to prevent this.

While at it, added a comment - the one atop PTRACE_EVENT block, saying
"Wait extended result codes for the above trace options", is not true
for PTRACE_EVENT_STOP.

Signed-off-by: Denys Vlasenko &lt;vda.linux@googlemail.com&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Reviewed-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Pedro Alves &lt;palves@redhat.com&gt;
Cc: Jan Kratochvil &lt;jan.kratochvil@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
@@ -61,7 +61,8 @@
 #define PTRACE_EVENT_EXEC	4
 #define PTRACE_EVENT_VFORK_DONE	5
 #define PTRACE_EVENT_EXIT	6
-#define PTRACE_EVENT_STOP	7
+/* Extended result codes which enabled by means other than options.  */
+#define PTRACE_EVENT_STOP	128
 
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD	1
