From 0af462f19e635ad522f28981238334620881badc Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 1 May 2023 17:42:06 +0200 Subject: [PATCH] debugobject: Ensure pool refill (again) 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 Signed-off-by: Thomas Gleixner Tested-by: Ido Schimmel Link: https://lore.kernel.org/r/871qk05a9d.ffs@tglx --- lib/debugobjects.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index b796799fadb2..003edc5ebd67 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -587,6 +587,16 @@ static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket 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, const struct debug_obj_descr *descr, int onstack) { @@ -595,12 +605,7 @@ __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack struct debug_obj *obj; unsigned long flags; - /* - * On RT enabled kernels the pool refill must happen in preemptible - * context: - */ - if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) - fill_pool(); + debug_objects_fill_pool(); db = get_bucket((unsigned long) addr); @@ -685,6 +690,8 @@ int debug_object_activate(void *addr, const struct debug_obj_descr *descr) if (!debug_objects_enabled) return 0; + debug_objects_fill_pool(); + db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); @@ -894,6 +901,8 @@ void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr) if (!debug_objects_enabled) return; + debug_objects_fill_pool(); + db = get_bucket((unsigned long) addr); raw_spin_lock_irqsave(&db->lock, flags); -- 2.25.1