From nobody Wed Dec 17 08:22:47 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 8AE37C41535 for ; Tue, 12 Dec 2023 00:14:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345454AbjLLAOI (ORCPT ); Mon, 11 Dec 2023 19:14:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345415AbjLLAOF (ORCPT ); Mon, 11 Dec 2023 19:14:05 -0500 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [IPv6:2001:41d0:203:375::ae]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98EFCAD for ; Mon, 11 Dec 2023 16:14:11 -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=1702340049; 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=x4Cn8Rdft153TNfaMCqmpUoRbUij/xgpu9Ka1HxHDYI=; b=UvkDjF/5ctTo0nGnQabktnmBPXGfus3/X3idORYN6B4D44rXq0KJToDsQKy9BeHFX8qw7b qQCY+W0sZZweOoacCTj/1cWItkpd82s9p4KPKbjHROXaD7+UwOj6FNmJAKaJ2G1O+XKX3R d6piyZ++vR5FIz/37yANY5B0lerp6zk= 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 , Tetsuo Handa , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov , syzbot+186b55175d8360728234@syzkaller.appspotmail.com Subject: [PATCH mm 2/4] kasan: handle concurrent kasan_record_aux_stack calls Date: Tue, 12 Dec 2023 01:14:01 +0100 Message-Id: <432a89fafce11244287c8af757e73a2eb22a5354.1702339432.git.andreyknvl@google.com> 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 kasan_record_aux_stack can be called concurrently on the same object. This might lead to a race condition when rotating the saved aux stack trace handles. Fix by introducing a spinlock to protect the aux stack trace handles in kasan_record_aux_stack. Reported-by: Tetsuo Handa Reported-by: syzbot+186b55175d8360728234@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/000000000000784b1c060b0074a2@google.com/ Signed-off-by: Andrey Konovalov --- This can be squashed into "kasan: use stack_depot_put for Generic mode" or left standalone. --- mm/kasan/generic.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 54e20b2bc3e1..ca5c75a1866c 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -35,6 +36,8 @@ #include "kasan.h" #include "../slab.h" =20 +DEFINE_SPINLOCK(aux_lock); + /* * All functions below always inlined so compiler could * perform better optimizations in each of __asan_loadX/__assn_storeX @@ -502,6 +505,8 @@ static void __kasan_record_aux_stack(void *addr, depot_= flags_t depot_flags) struct kmem_cache *cache; struct kasan_alloc_meta *alloc_meta; void *object; + depot_stack_handle_t new_handle, old_handle; + unsigned long flags; =20 if (is_kfence_address(addr) || !slab) return; @@ -512,9 +517,15 @@ static void __kasan_record_aux_stack(void *addr, depot= _flags_t depot_flags) if (!alloc_meta) return; =20 - stack_depot_put(alloc_meta->aux_stack[1]); + new_handle =3D kasan_save_stack(0, depot_flags); + + spin_lock_irqsave(&aux_lock, flags); + old_handle =3D alloc_meta->aux_stack[1]; alloc_meta->aux_stack[1] =3D alloc_meta->aux_stack[0]; - alloc_meta->aux_stack[0] =3D kasan_save_stack(0, depot_flags); + alloc_meta->aux_stack[0] =3D new_handle; + spin_unlock_irqrestore(&aux_lock, flags); + + stack_depot_put(old_handle); } =20 void kasan_record_aux_stack(void *addr) --=20 2.25.1