From nobody Sun Dec 14 05:59:25 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29CBFC2BB3F for ; Mon, 20 Nov 2023 17:51:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232734AbjKTRvy (ORCPT ); Mon, 20 Nov 2023 12:51:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234384AbjKTRvY (ORCPT ); Mon, 20 Nov 2023 12:51:24 -0500 Received: from out-183.mta1.migadu.com (out-183.mta1.migadu.com [95.215.58.183]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10C69D5F for ; Mon, 20 Nov 2023 09:50:45 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1700502644; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Qc2DDhk7eSddbt2Q3kjJLSbCNGbLZWOl9JsGZF81sG4=; b=SjlBdcCRByh5PrG2MOhc8aFxhKI3iaDpNaxTHUEIaJyLo5jT4ZNFXt6Bt3sd9u50OfOKSg CaLcy9JTN+VHkT3VWRZiUR5iYfkV9u6uxcxdsNTqWTVW/b0iVcXorrCGAHL4XcSBww8rJU PD/hyomJcMBAWfjY4j+0VCD4sMN1M4g= From: andrey.konovalov@linux.dev To: Andrew Morton Cc: Andrey Konovalov , Marco Elver , Alexander Potapenko , Dmitry Vyukov , Vlastimil Babka , kasan-dev@googlegroups.com, Evgenii Stepanov , Oscar Salvador , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v4 20/22] kasan: use stack_depot_put for tag-based modes Date: Mon, 20 Nov 2023 18:47:18 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Andrey Konovalov Make tag-based KASAN modes evict stack traces from the stack depot once they are evicted from the stack ring. Internally, pass STACK_DEPOT_FLAG_GET to stack_depot_save_flags (via kasan_save_stack) to increment the refcount when saving a new entry to stack ring and call stack_depot_put when removing an entry from stack ring. Reviewed-by: Alexander Potapenko Signed-off-by: Andrey Konovalov --- Changes v1->v2: - Adapt to the stack depot API change. - Drop READ_ONCE when reading entry->stack. --- mm/kasan/tags.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index b6c017e670d8..739ae997463d 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -97,12 +97,13 @@ static void save_stack_info(struct kmem_cache *cache, v= oid *object, gfp_t gfp_flags, bool is_free) { unsigned long flags; - depot_stack_handle_t stack; + depot_stack_handle_t stack, old_stack; u64 pos; struct kasan_stack_ring_entry *entry; void *old_ptr; =20 - stack =3D kasan_save_stack(gfp_flags, STACK_DEPOT_FLAG_CAN_ALLOC); + stack =3D kasan_save_stack(gfp_flags, + STACK_DEPOT_FLAG_CAN_ALLOC | STACK_DEPOT_FLAG_GET); =20 /* * Prevent save_stack_info() from modifying stack ring @@ -121,6 +122,8 @@ static void save_stack_info(struct kmem_cache *cache, v= oid *object, if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR)) goto next; /* Busy slot. */ =20 + old_stack =3D entry->stack; + entry->size =3D cache->object_size; entry->pid =3D current->pid; entry->stack =3D stack; @@ -129,6 +132,9 @@ static void save_stack_info(struct kmem_cache *cache, v= oid *object, entry->ptr =3D object; =20 read_unlock_irqrestore(&stack_ring.lock, flags); + + if (old_stack) + stack_depot_put(old_stack); } =20 void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t f= lags) --=20 2.25.1