mm: kfence: apply kmemleak_ignore_phys on early allocated pool

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2151065

commit 07313a2
Author: Yee Lee <yee.lee@mediatek.com>
Date:   Tue, 28 Jun 2022 19:37:11 +0800

    mm: kfence: apply kmemleak_ignore_phys on early allocated pool

    This patch solves two issues.

    (1) The pool allocated by memblock needs to unregister from
    kmemleak scanning. Apply kmemleak_ignore_phys to replace the
    original kmemleak_free as its address now is stored in the phys tree.

    (2) The pool late allocated by page-alloc doesn't need to unregister.
    Move out the freeing operation from its call path.

    Link: https://lkml.kernel.org/r/20220628113714.7792-2-yee.lee@mediatek.com
    Fixes: 0c24e06 ("mm: kmemleak: add rbtree and store physical address for objects allocated with PA")
    Signed-off-by: Yee Lee <yee.lee@mediatek.com>
    Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
    Suggested-by: Marco Elver <elver@google.com>
    Reviewed-by: Marco Elver <elver@google.com>
    Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Waiman Long <longman@redhat.com>

Author: Waiman-Long

mm/kfence/core.c

@@ -591,14 +591,6 @@ static unsigned long kfence_init_pool(void)
 		addr += 2 * PAGE_SIZE;
 	}
 
-	/*
-	 * The pool is live and will never be deallocated from this point on.
-	 * Remove the pool object from the kmemleak object tree, as it would
-	 * otherwise overlap with allocations returned by kfence_alloc(), which
-	 * are registered with kmemleak through the slab post-alloc hook.
-	 */
-	kmemleak_free(__kfence_pool);
-
 	return 0;
 }
 
@@ -611,8 +603,16 @@ static bool __init kfence_init_pool_early(void)
 
 	addr = kfence_init_pool();
 
-	if (!addr)
+	if (!addr) {
+		/*
+		 * The pool is live and will never be deallocated from this point on.
+		 * Ignore the pool object from the kmemleak phys object tree, as it would
+		 * otherwise overlap with allocations returned by kfence_alloc(), which
+		 * are registered with kmemleak through the slab post-alloc hook.
+		 */
+		kmemleak_ignore_phys(__pa(__kfence_pool));
 		return true;
+	}
 
 	/*
 	 * Only release unprotected pages, and do not try to go back and change