ftrace: Add cond_resched() to ftrace_graph_set_hash()

When the kernel contains a large number of functions that can be traced,
the loop in ftrace_graph_set_hash() may take a lot of time to execute.
This may trigger the softlockup watchdog.

Add cond_resched() within the loop to allow the kernel to remain
responsive even when processing a large number of functions.

This matches the cond_resched() that is used in other locations of the
code that iterates over all functions that can be traced.

Cc: [email protected]
Fixes: b9b0c831be ("ftrace: Convert graph filter to use hash tables")
Link: https://lore.kernel.org/[email protected]
Signed-off-by: zhoumin <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

kernel/trace/ftrace.c

@@ -6855,6 +6855,7 @@ ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
 				}
 			}
 		}
+		cond_resched();
 	} while_for_each_ftrace_rec();
 
 	return fail ? -EINVAL : 0;