Merge tag 'trace-v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

torvalds · torvalds · commit 00d959333513 · 2017-05-08T20:36:38.000-07:00
Pull more tracing updates from Steven Rostedt:
 "These are three simple changes.

  The first one is just a switch from using strcpy() to strlcpy().
  Someone thought that it may cause an overflow bug, but since it only
  copies comms into a pre-allocated array of TASK_COMM_LEN, and no comm
  should ever be bigger than that, nor not end with a nul character,
  this change is more of a safety precaution than fixing anything that
  is actually broken.

  The other two changes are simply cleaning and optimizing some code"

* tag 'trace-v4.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Simplify ftrace_match_record() even more
  ftrace: Remove an unneeded condition
  tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
@@ -3631,22 +3631,20 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
 		/* blank module name to match all modules */
 		if (!mod_g->len) {
 			/* blank module globbing: modname xor exclude_mod */
-			if ((!exclude_mod) != (!modname))
+			if (!exclude_mod != !modname)
 				goto func_match;
 			return 0;
 		}
 
-		/* not matching the module */
-		if (!modname || !mod_matches) {
-			if (exclude_mod)
-				goto func_match;
-			else
-				return 0;
-		}
-
-		if (mod_matches && exclude_mod)
+		/*
+		 * exclude_mod is set to trace everything but the given
+		 * module. If it is set and the module matches, then
+		 * return 0. If it is not set, and the module doesn't match
+		 * also return 0. Otherwise, check the function to see if
+		 * that matches.
+		 */
+		if (!mod_matches == !exclude_mod)
 			return 0;
-
 func_match:
 		/* blank search means to match all funcs in the mod */
 		if (!func_g->len)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
@@ -1976,7 +1976,7 @@ static void __trace_find_cmdline(int pid, char comm[])
 
 	map = savedcmd->map_pid_to_cmdline[pid];
 	if (map != NO_CMDLINE_MAP)
-		strcpy(comm, get_saved_cmdlines(map));
+		strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
 	else
 		strcpy(comm, "<...>");
 }

Original file line number	Diff line number	Diff line change
`@@ -1976,7 +1976,7 @@ static void __trace_find_cmdline(int pid, char comm[])`
`1976`	`1976`
`1977`	`1977`	`map = savedcmd->map_pid_to_cmdline[pid];`
`1978`	`1978`	`if (map != NO_CMDLINE_MAP)`
`1979`		`- strcpy(comm, get_saved_cmdlines(map));`
	`1979`	`+ strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);`
`1980`	`1980`	`else`
`1981`	`1981`	`strcpy(comm, "<...>");`
`1982`	`1982`	`}`