Commit 4eff7d62 authored by Liu Shixin's avatar Liu Shixin Committed by Andrew Morton
Browse files

Revert "mm/kmemleak: move the initialisation of object to __link_object" 

Patch series "Fix invalid wait context of set_track_prepare()".

Geert reported an invalid wait context[1] which is resulted by moving
set_track_prepare() inside kmemleak_lock.  This is not allowed because in
RT mode, the spinlocks can be preempted but raw_spinlocks can not, so it
is not allowd to acquire spinlocks while holding raw_spinlocks.  The
second patch fix same problem in kmemleak_update_trace().


This patch (of 2):

Move the initialisation of object back to__alloc_object() because
set_track_prepare() attempt to acquire zone->lock(spinlocks) while
__link_object is holding kmemleak_lock(raw_spinlocks).  This is not right
for RT mode.

This reverts commit 245245c2 ("mm/kmemleak: move the initialisation
of object to __link_object").

Link: https://lkml.kernel.org/r/20231115082138.2649870-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20231115082138.2649870-2-liushixin2@huawei.com


Fixes: 245245c2 ("mm/kmemleak: move the initialisation of object to __link_object")
Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
Reported-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Closes: https://lore.kernel.org/linux-mm/CAMuHMdWj0UzwNaxUvcocTfh481qRJpOWwXxsJCTJfu1oCqvgdA@mail.gmail.com/

 [1]
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Patrick Wang <patrick.wang.shcn@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 727d16f1

mm/kmemleak.c

+19 −17
Original line number Diff line number Diff line
@@ -642,32 +642,16 @@ static struct kmemleak_object *__alloc_object(gfp_t gfp) 
	if (!object) {

		pr_warn("Cannot allocate a kmemleak_object structure\n");

		kmemleak_disable();

		return NULL;

	}



	return object;

}



static int __link_object(struct kmemleak_object *object, unsigned long ptr,

			 size_t size, int min_count, bool is_phys)

{



	struct kmemleak_object *parent;

	struct rb_node **link, *rb_parent;

	unsigned long untagged_ptr;

	unsigned long untagged_objp;



	INIT_LIST_HEAD(&object->object_list);

	INIT_LIST_HEAD(&object->gray_list);

	INIT_HLIST_HEAD(&object->area_list);

	raw_spin_lock_init(&object->lock);

	atomic_set(&object->use_count, 1);

	object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);

	object->pointer = ptr;

	object->size = kfence_ksize((void *)ptr) ?: size;

	object->excess_ref = 0;

	object->min_count = min_count;

	object->count = 0;			/* white color initially */

	object->jiffies = jiffies;

	object->checksum = 0;

	object->del_state = 0;
@@ -692,6 +676,24 @@ static int __link_object(struct kmemleak_object *object, unsigned long ptr, 
	/* kernel backtrace */

	object->trace_handle = set_track_prepare();



	return object;

}



static int __link_object(struct kmemleak_object *object, unsigned long ptr,

			 size_t size, int min_count, bool is_phys)

{



	struct kmemleak_object *parent;

	struct rb_node **link, *rb_parent;

	unsigned long untagged_ptr;

	unsigned long untagged_objp;



	object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);

	object->pointer = ptr;

	object->size = kfence_ksize((void *)ptr) ?: size;

	object->min_count = min_count;

	object->jiffies = jiffies;



	untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);

	/*

	 * Only update min_addr and max_addr with object