From: Thomas Gleixner tglx@linutronix.de
commit 0af462f19e635ad522f28981238334620881badc upstream.
The recent fix to ensure atomicity of lookup and allocation inadvertently broke the pool refill mechanism.
Prior to that change debug_objects_activate() and debug_objecs_assert_init() invoked debug_objecs_init() to set up the tracking object for statically initialized objects. That's not longer the case and debug_objecs_init() is now the only place which does pool refills.
Depending on the number of statically initialized objects this can be enough to actually deplete the pool, which was observed by Ido via a debugobjects OOM warning.
Restore the old behaviour by adding explicit refill opportunities to debug_objects_activate() and debug_objecs_assert_init().
Fixes: 63a759694eed ("debugobject: Prevent init race with static objects") Reported-by: Ido Schimmel idosch@nvidia.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Ido Schimmel idosch@nvidia.com Link: https://lore.kernel.org/r/871qk05a9d.ffs@tglx Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/debugobjects.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
--- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -563,6 +563,16 @@ static struct debug_obj *lookup_object_o return NULL; }
+static void debug_objects_fill_pool(void) +{ + /* + * On RT enabled kernels the pool refill must happen in preemptible + * context: + */ + if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) + fill_pool(); +} + static void __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack) { @@ -571,7 +581,7 @@ __debug_object_init(void *addr, struct d struct debug_obj *obj; unsigned long flags;
- fill_pool(); + debug_objects_fill_pool();
db = get_bucket((unsigned long) addr);
@@ -656,6 +666,8 @@ int debug_object_activate(void *addr, st if (!debug_objects_enabled) return 0;
+ debug_objects_fill_pool(); + db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags); @@ -865,6 +877,8 @@ void debug_object_assert_init(void *addr if (!debug_objects_enabled) return;
+ debug_objects_fill_pool(); + db = get_bucket((unsigned long) addr);
raw_spin_lock_irqsave(&db->lock, flags);