From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Ido Schimmel <idosch@xxxxxxxxxx>
Link: https://lore.kernel.org/r/871qk05a9d.ffs@tglx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
lib/debugobjects.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -460,6 +460,16 @@ 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)
{
@@ -468,7 +478,7 @@ __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);
@@ -553,6 +563,8 @@ 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);
@@ -762,6 +774,8 @@ 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);
