From: Ahmed Ehab <bottaawesome633@xxxxxxxxx> Checking if the lockdep_map->name will change when setting the subclass. It shouldn't change so that the lock class and subclass will have the same name Reported-by: <syzbot+7f4a6f7f7051474e40ad@xxxxxxxxxxxxxxxxxxxxxxxxx> Fixes: de8f5e4f2dc1f ("lockdep: Introduce wait-type checks") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Ahmed Ehab <bottaawesome633@xxxxxxxxx> --- v3->v4: - Fixed subject line truncation. lib/locking-selftest.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 6f6a5fc85b42..aeed613799ca 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -2710,6 +2710,25 @@ static void local_lock_3B(void) } + /** + * after setting the subclass the lockdep_map.name changes + * if we initialize a new string literal for the subclass + * we will have a new name pointer + */ +static void class_subclass_X1_name_test(void) +{ + printk(" --------------------------------------------------------------------------\n"); + printk(" | class and subclass name test|\n"); + printk(" ---------------------\n"); + const char *name_before_setting_subclass = rwsem_X1.dep_map.name; + const char *name_after_setting_subclass; + + WARN_ON(!rwsem_X1.dep_map.name); + lockdep_set_subclass(&rwsem_X1, 1); + name_after_setting_subclass = rwsem_X1.dep_map.name; + WARN_ON(name_before_setting_subclass != name_after_setting_subclass); +} + static void local_lock_tests(void) { printk(" --------------------------------------------------------------------------\n"); @@ -2916,6 +2935,8 @@ void locking_selftest(void) local_lock_tests(); + class_subclass_X1_name_test(); + print_testname("hardirq_unsafe_softirq_safe"); dotest(hardirq_deadlock_softirq_not_deadlock, FAILURE, LOCKTYPE_SPECIAL); pr_cont("\n"); -- 2.45.2