From patchwork Thu Feb 13 17:36:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qian Cai X-Patchwork-Id: 11380903 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 79DB81395 for ; Thu, 13 Feb 2020 17:36:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4715C21734 for ; Thu, 13 Feb 2020 17:36:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="kjBiP+F3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4715C21734 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8DC7D6B0596; Thu, 13 Feb 2020 12:36:42 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 8B1E66B0593; Thu, 13 Feb 2020 12:36:42 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7A2146B0597; Thu, 13 Feb 2020 12:36:42 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id 5DEF96B0593 for ; Thu, 13 Feb 2020 12:36:42 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 05758180AD817 for ; Thu, 13 Feb 2020 17:36:42 +0000 (UTC) X-FDA: 76485808644.28.laugh63_3a729dad7d20f X-Spam-Summary: 2,0,0,8508b7ebdb7719c1,d41d8cd98f00b204,cai@lca.pw,:akpm@linux-foundation.org:catalin.marinas@arm.com:elver@google.com::linux-kernel@vger.kernel.org:cai@lca.pw,RULES_HIT:41:355:379:541:800:960:966:988:989:1260:1345:1437:1535:1543:1711:1730:1747:1777:1792:1981:2194:2196:2199:2200:2393:2559:2562:2693:2904:2918:3138:3139:3140:3141:3142:3354:3865:3866:3867:3870:3872:4321:4385:5007:6261:6653:7903:8603:10004:11026:11658:11914:12043:12296:12297:12438:12517:12519:12555:12895:13161:13229:14018:14096:14104:14181:14394:14721:21067:21080:21444:21627:21990:30012:30054,0,RBL:209.85.219.66:@lca.pw:.lbl8.mailshell.net-62.2.0.100 66.100.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:27,LUA_SUMMARY:none X-HE-Tag: laugh63_3a729dad7d20f X-Filterd-Recvd-Size: 5944 Received: from mail-qv1-f66.google.com (mail-qv1-f66.google.com [209.85.219.66]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Thu, 13 Feb 2020 17:36:41 +0000 (UTC) Received: by mail-qv1-f66.google.com with SMTP id q9so2063893qvu.7 for ; Thu, 13 Feb 2020 09:36:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=from:to:cc:subject:date:message-id; bh=O0HHfKHIMlC0RjUcckPaUV2bXRGbWu90N+8L8NiO3VY=; b=kjBiP+F3hV0eEn1QW0XYHbEKbm/EmTOaUFbFEJ7s0yyrhmHX4masMc+lyAJrxjljV1 14mpFaF5/lOF/RDUrA4bn85pFWB9fL1AmduugFYFoe7xQJcFXOXvq32/Oe+y+7x0b+72 S4bNcG1TuHk/Sxn+dmQlTQnjqznoue8EKQXHDELcC3iTKccMEakh5DI9yMXf6e3D/BY/ ky5GksqbaNYXuBvWpIOw8qVoAkA0RlBG6a8661TmgaZqkS5dArhkK7nhUfM8vv/TSNSr a6ic5JeiGOdSJtYgvJBEMsqZpCgv0NsdorcWTQy/DPau/v8LY0evhhLYEUZObkD3Up1t 5ISQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=O0HHfKHIMlC0RjUcckPaUV2bXRGbWu90N+8L8NiO3VY=; b=Y4zhkxKiwGd/ESHKu8APqvypr2iOG03oQ4EuWvaa9J2bDh9my5pODIInacgNFmoYRl ihSTvtlwTPlcgXf1HLSM/LbqCdu2fS2KhlNRvuK6x1fORFmQ2T+dR0TIbeUqU3Xcpt0I ca5evSGTmgxrEQjHXULWfx6oj3FWrztV0KgubA8PkkCWkQNoPpG7S4WXZ+Rs6flxvV1N xFZhPPBxz8ceeFqA77KmXJUVxbubMg4HpktXa/CPHrZ1rMWaoaEDOoeey1C2vmWMZsUm CmQQ232B6uQ7BfwFt9WuBtz1lt+1aw2+6JhOpumVZaxUOjkKziZeDY73aWgugQuCLdPH /cUA== X-Gm-Message-State: APjAAAVwVg+7+scS75vrWxErkKdTFc4748ugNWOz8TQTWVbMHcZ0rzL0 l9dz7axtpGT1grbN732fRDaMngRfX1ZQcQ== X-Google-Smtp-Source: APXvYqzjjdyf+MJULWzPS8PZx6PvEQ2smSMkicTbCD90d06Eu4erfG/EMBgRqee484nSEbCgR/viSA== X-Received: by 2002:ad4:5888:: with SMTP id dz8mr12736260qvb.204.1581615400917; Thu, 13 Feb 2020 09:36:40 -0800 (PST) Received: from qcai.nay.com (nat-pool-bos-t.redhat.com. [66.187.233.206]) by smtp.gmail.com with ESMTPSA id 65sm1795043qtc.4.2020.02.13.09.36.39 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Feb 2020 09:36:40 -0800 (PST) From: Qian Cai To: akpm@linux-foundation.org Cc: catalin.marinas@arm.com, elver@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH -next v2] mm/kmemleak: annotate various data races obj->ptr Date: Thu, 13 Feb 2020 12:36:30 -0500 Message-Id: <1581615390-9720-1-git-send-email-cai@lca.pw> X-Mailer: git-send-email 1.8.3.1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The value of object->pointer could be accessed concurrently as noticed by KCSAN, write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12: do_raw_spin_lock+0x114/0x200 debug_spin_lock_after at kernel/locking/spinlock_debug.c:91 (inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115 _raw_spin_lock+0x40/0x50 __handle_mm_fault+0xa9e/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60: crc32_le_base+0x67/0x350 crc32_le_base+0x67/0x350: crc32_body at lib/crc32.c:106 (inlined by) crc32_le_generic at lib/crc32.c:179 (inlined by) crc32_le at lib/crc32.c:197 kmemleak_scan+0x528/0xd90 update_checksum at mm/kmemleak.c:1172 (inlined by) kmemleak_scan at mm/kmemleak.c:1497 kmemleak_scan_thread+0xcc/0xfa kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 write to 0xffff939bf07b95b8 of 4 bytes by interrupt on cpu 119: __free_object+0x884/0xcb0 __free_object at lib/debugobjects.c:359 __debug_check_no_obj_freed+0x19d/0x370 debug_check_no_obj_freed+0x41/0x4b slab_free_freelist_hook+0xfb/0x1c0 kmem_cache_free+0x10c/0x3a0 free_object_rcu+0x1ca/0x260 rcu_core+0x677/0xcc0 rcu_core_si+0x17/0x20 __do_softirq+0xd9/0x57c run_ksoftirqd+0x29/0x50 smpboot_thread_fn+0x222/0x3f0 kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 read to 0xffff939bf07b95b8 of 8 bytes by task 838 on cpu 109: scan_block+0x69/0x190 scan_block at mm/kmemleak.c:1250 kmemleak_scan+0x249/0xd90 scan_large_block at mm/kmemleak.c:1309 (inlined by) kmemleak_scan at mm/kmemleak.c:1434 kmemleak_scan_thread+0xcc/0xfa kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 crc32() will dereference object->pointer. If a shattered value was returned due to a data race, it will be corrected in the next scan. scan_block() will dereference a range of addresses (e.g., percpu sections) to search for valid pointers. Even if a data race heppens, it will cause no issue because the code here does not care about the exact value of a non-pointer. Thus, mark them as intentional data races using the data_race() macro. Signed-off-by: Qian Cai Acked-by: Catalin Marinas --- v2: add a missing annotation. mm/kmemleak.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 3a4259eeb5a0..aa6832432d6a 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1169,7 +1169,12 @@ static bool update_checksum(struct kmemleak_object *object) u32 old_csum = object->checksum; kasan_disable_current(); - object->checksum = crc32(0, (void *)object->pointer, object->size); + /* + * crc32() will dereference object->pointer. If an unstable value was + * returned due to a data race, it will be corrected in the next scan. + */ + object->checksum = data_race(crc32(0, (void *)object->pointer, + object->size)); kasan_enable_current(); return object->checksum != old_csum; @@ -1243,7 +1248,7 @@ static void scan_block(void *_start, void *_end, break; kasan_disable_current(); - pointer = *ptr; + pointer = data_race(*ptr); kasan_enable_current(); untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);