ftrace: Add cond_resched() to ftrace_graph_set_hash()

JIRA: https://issues.redhat.com/browse/RHEL-115358

CVE: CVE-2025-37940

Conflicts: Context change from missing commit 8b0cb3a ("ftrace:
Use guard to take ftrace_lock in ftrace_graph_set_hash()")

commit 42ea22e
Author: zhoumin <teczm@foxmail.com>
Date:   Tue Apr 1 01:00:34 2025 +0800

    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: stable@vger.kernel.org
    Fixes: b9b0c83 ("ftrace: Convert graph filter to use hash tables")
    Link: https://lore.kernel.org/tencent_3E06CE338692017B5809534B9C5C03DA7705@qq.com
    Signed-off-by: zhoumin <teczm@foxmail.com>
    Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>

Author: jeromemarchand

kernel/trace/ftrace.c

@@ -6848,6 +6848,7 @@ ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
 				}
 			}
 		}
+		cond_resched();
 	} while_for_each_ftrace_rec();
 out:
 	mutex_unlock(&ftrace_lock);