rcutorture: Don't do busted forward-progress testing

Paul E. McKenney · Paul E. McKenney · commit 5ac7cdc29897 · 2018-12-01T12:45:42.000-08:00
The "busted" rcutorture type is an intentionally broken implementation
of RCU.  Doing forward-progress testing on this implementation is not
particularly meaningful on the one hand and can result in fatal abuse
of the memory allocator on the other.  This commit therefore disables
forward-progress testing of the "busted" rcutorture type.

Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@linux.ibm.com&gt;
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
@@ -1900,7 +1900,8 @@ static int __init rcu_torture_fwd_prog_init(void)
 {
 	if (!fwd_progress)
 		return 0; /* Not requested, so don't do it. */
-	if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0) {
+	if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
+	    cur_ops == &rcu_busted_ops) {
 		VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
 		return 0;
 	}

Original file line number	Diff line number	Diff line change
`@@ -1900,7 +1900,8 @@ static int __init rcu_torture_fwd_prog_init(void)`
`1900`	`1900`	`{`
`1901`	`1901`	`if (!fwd_progress)`
`1902`	`1902`	`return 0; /* Not requested, so don't do it. */`
`1903`		`- if (!cur_ops->stall_dur \|\| cur_ops->stall_dur() <= 0) {`
	`1903`	`+ if (!cur_ops->stall_dur \|\| cur_ops->stall_dur() <= 0 \|\|`
	`1904`	`+ cur_ops == &rcu_busted_ops) {`
`1904`	`1905`	`VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");`
`1905`	`1906`	`return 0;`
`1906`	`1907`	`}`