From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70AC2C28CF5 for ; Wed, 26 Jan 2022 19:26:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DC0BB6B0080; Wed, 26 Jan 2022 14:26:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D6E8E6B0082; Wed, 26 Jan 2022 14:26:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C5CDA6B0083; Wed, 26 Jan 2022 14:26:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id B681B6B0080 for ; Wed, 26 Jan 2022 14:26:12 -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 7CFD018194D79 for ; Wed, 26 Jan 2022 19:26:12 +0000 (UTC) X-FDA: 79073419026.28.D5E311D Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) by imf19.hostedemail.com (Postfix) with ESMTP id 214B51A0009 for ; Wed, 26 Jan 2022 19:26:11 +0000 (UTC) Received: by mail-pl1-f178.google.com with SMTP id k17so537781plk.0 for ; Wed, 26 Jan 2022 11:26:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=FVYHc2+BFBni6BKS9KzbZHsth+59VjQdJh4ifViuJgU=; b=mod3qenkSqfRqSY3ZEMtFoM6tvXmaDwLD363+n8GjuMDUYd0uJQVFw2qsKhxjHy/tq yMF49nGy+Y3OAy5PGHZ3ZBVSFMgQdGGO29IhUtDFsASlRjyBLC/tzkvpmBckhXDFQIjD hRdXnIvdv+3lTTTND8ZBV1rznplZiVNaV61xYJIxtF8RkoXz8VFCGU6A+YiO5Kor6pJd haTklqK9vuYnMOEjZx1H27hGr6T293qJ11qgSOHBxnc9vcvz2PYtQvSThT15TkKDwxgg s2HhOaHN2TKqXCtV687QrfCPgDOsvxzo5EfT6xqL+ZHl4YAvOm1b87KWyRI7xeQ2NBIX gdeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=FVYHc2+BFBni6BKS9KzbZHsth+59VjQdJh4ifViuJgU=; b=0cyqUrSdyNp6AaknBDZZB6dE3wyYGeA1BdPVIFsL+gGmtzWQ/2mDGX1SE9zgCBa+2n HgDw6jVR8JoCrxTgO8cZ4TFXHFcrm8zpDUsn9kgZ0oY7S/yZz6A+luiW3Qpc2LG4AmMT FGhyFBhWpZpjdClkkO47yDWS0wTxlHSXxjr1YL0yQRY2XJUZd5UcPPu2IZKWP6+xb0RQ cQhfYRDl+PpqJZnkdwtCYHUdwbOY1XEIrpbcOBkzm+PYqVnA6gsc9hdBz2iwEQ+rwW0h YtJMkvajS5z5kwxgywm+zdtLj3cFqRL23EV5vJvnhp4z/8beiUHjA0vb+nTELvTe55Ot anfg== X-Gm-Message-State: AOAM533Ebr7MZ9VbOVgGkO4v5fgxEBWp/at2YgVi3KXMle8eQXDzppGE 12Vb6zPnUExuA1us1TghPZlXOQ== X-Google-Smtp-Source: ABdhPJwzi/oqq3KEtgTD8w0cfXbUW9DYcBt6wHefVZe2VJHleRDmpI9yKwxF/T++uqSUiNy6IolADQ== X-Received: by 2002:a17:902:eb52:: with SMTP id i18mr56786pli.143.1643225170654; Wed, 26 Jan 2022 11:26:10 -0800 (PST) Received: from [2620:15c:29:204:925c:a455:6d75:1ac8] ([2620:15c:29:204:925c:a455:6d75:1ac8]) by smtp.gmail.com with ESMTPSA id 13sm2776911pfm.161.2022.01.26.11.26.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Jan 2022 11:26:10 -0800 (PST) Date: Wed, 26 Jan 2022 11:26:09 -0800 (PST) From: David Rientjes To: Pasha Tatashin cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, pjt@google.com, weixugc@google.com, gthelen@google.com, mingo@redhat.com, will@kernel.org, rppt@kernel.org, dave.hansen@linux.intel.com, hpa@zytor.com, aneesh.kumar@linux.ibm.com, jirislaby@kernel.org, songmuchun@bytedance.com, qydwhotmail@gmail.com, hughd@google.com, ziy@nvidia.com, anshuman.khandual@arm.com Subject: Re: [PATCH v4 4/4] mm/page_table_check: check entries at pmd levels In-Reply-To: <20220126183637.1840960-5-pasha.tatashin@soleen.com> Message-ID: References: <20220126183637.1840960-1-pasha.tatashin@soleen.com> <20220126183637.1840960-5-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 214B51A0009 X-Stat-Signature: dyz39ye646cj8d65ntbatwqtocmgu3ua Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=mod3qenk; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf19.hostedemail.com: domain of rientjes@google.com designates 209.85.214.178 as permitted sender) smtp.mailfrom=rientjes@google.com X-Rspam-User: nil X-HE-Tag: 1643225171-134914 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: On Wed, 26 Jan 2022, Pasha Tatashin wrote: > syzbot detected a case where the page table counters were not properly > updated. > > syzkaller login: ------------[ cut here ]------------ > kernel BUG at mm/page_table_check.c:162! > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 3099 Comm: pasha Not tainted 5.16.0+ #48 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIO4 > RIP: 0010:__page_table_check_zero+0x159/0x1a0 > Code: 7d 3a b2 ff 45 39 f5 74 2a e8 43 38 b2 ff 4d 85 e4 01 > RSP: 0018:ffff888010667418 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000 > RDX: ffff88800cea8680 RSI: ffffffff81becaf9 RDI: 0000000003 > RBP: ffff888010667450 R08: 0000000000000001 R09: 0000000000 > R10: ffffffff81becaab R11: 0000000000000001 R12: ffff888008 > R13: 0000000000000001 R14: 0000000000000200 R15: dffffc0000 > FS: 0000000000000000(0000) GS:ffff888035e00000(0000) knlG0 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007ffd875cad00 CR3: 00000000094ce000 CR4: 0000000000 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000 > Call Trace: > > free_pcp_prepare+0x3be/0xaa0 > free_unref_page+0x1c/0x650 > ? trace_hardirqs_on+0x6a/0x1d0 > free_compound_page+0xec/0x130 > free_transhuge_page+0x1be/0x260 > __put_compound_page+0x90/0xd0 > release_pages+0x54c/0x1060 > ? filemap_remove_folio+0x161/0x210 > ? lock_downgrade+0x720/0x720 > ? __put_page+0x150/0x150 > ? filemap_free_folio+0x164/0x350 > __pagevec_release+0x7c/0x110 > shmem_undo_range+0x85e/0x1250 > ... > > The repro involved having a huge page that is split due to uprobe event > temporarily replacing one of the pages in the huge page. Later the huge > page was combined again, but the counters were off, as the PTE level > was not properly updated. > > Make sure that when PMD is cleared and prior to freeing the level the > PTEs are updated. > > Fixes: df4e817b7108 ("mm: page table check") > > Signed-off-by: Pasha Tatashin Acked-by: David Rientjes