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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F22FC4332F for ; Fri, 25 Mar 2022 01:46:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355124AbiCYBrl (ORCPT ); Thu, 24 Mar 2022 21:47:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357656AbiCYBr3 (ORCPT ); Thu, 24 Mar 2022 21:47:29 -0400 Received: from mail-yw1-x1132.google.com (mail-yw1-x1132.google.com [IPv6:2607:f8b0:4864:20::1132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06D159D4E0 for ; Thu, 24 Mar 2022 18:44:32 -0700 (PDT) Received: by mail-yw1-x1132.google.com with SMTP id 00721157ae682-2e6650cde1bso68845367b3.12 for ; Thu, 24 Mar 2022 18:44:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6C1MiK2JBH1dTA/prMrmf+ttqe2Acvbmx0mhdpvszJ8=; b=qDnVP63bmla7Or6NurBxPJNTEhoxKm9iNRNnN+VkXopisHaUnwNODLhCLXI78xhN17 Se4VSoarjGMh5dIjpAYb/qeQdvR/h0YD/T0ad9o+DeuzscOiHFnBHwrPhSziFcLVA7pF qYfaenDvXDZzO47+2ebGuLOHMymLN4rm3ECK6wQoXz48V9kQusQczwKa0jZ4LNRBZ1oV fluHVr3rz5LG4UmUU9zxnyBLjA0aBziq1xAQXYZpJpDm/K0YVax48CETR1j7n6jWfZpu jil0lKeiD4KRrAbyO+kofxpZE5XlxHBzTkuoZIm3g0NuDQHUaEssG3UEtq3Ma/J7ThJY xBWQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6C1MiK2JBH1dTA/prMrmf+ttqe2Acvbmx0mhdpvszJ8=; b=Dl/d6X1H7DfTT7oqDJICjLdaaZNNq4D5ytMMJW/eQztyk4LrwKyUkC9EJUC/sVjIcA Ul7fnHgoD8md+ZlH8ya/5fm629dGdFcPjBkAsZHekp2O8Qgtad5Tg5ighUZyAxi4hSZI 3PY283lF6nRQu/7EAXxqEt2r3ZfsJ5G3aeXP5ZyRmGUqJz6BQfZij9DKCQVh93uG1jnu WQvtdJ5c6VUnGREVgzfFjRv69It7AlzaKqZ4mOdEE6KRUAdksZ9Frodp1G1+DcA0wE8k Qs3TK9YH0WddIQTVqRxULz3rz2ssjQPIPYOsK+a85vS78HB5vkilolE82k0X8FqVRAEs y9jA== X-Gm-Message-State: AOAM530xrRQU4F6XPQrBHmhhiGbwcUBV3LLDkKP4LntYAh7VXIJt622B d9OgVCSmipq3N9/yVNIjmUdb/TzDE+HjOBpcHR6KCSEIs/qpYA== X-Google-Smtp-Source: ABdhPJxJqyASCYtHv3Pm1jkdaLKDI2gwBxP2Hx07HZA7/4CPpleAOda8/wG9UI6ImIvOAu/zNbavc6lv0WME2kZXQ28= X-Received: by 2002:a81:1c4f:0:b0:2e5:9db3:7a8e with SMTP id c76-20020a811c4f000000b002e59db37a8emr7691833ywc.319.1648172671241; Thu, 24 Mar 2022 18:44:31 -0700 (PDT) MIME-Version: 1.0 References: <0000000000009901d505dafc07b3@google.com> In-Reply-To: From: Muchun Song Date: Fri, 25 Mar 2022 09:43:51 +0800 Message-ID: Subject: Re: [syzbot] general protection fault in list_lru_add To: Linus Torvalds Cc: syzbot , Andrew Morton , Dmitry Vyukov , Linux Kernel Mailing List , Linux-MM , syzkaller-bugs Content-Type: multipart/mixed; boundary="00000000000099e40505db011a51" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --00000000000099e40505db011a51 Content-Type: text/plain; charset="UTF-8" On Fri, Mar 25, 2022 at 3:47 AM Linus Torvalds wrote: > > On Thu, Mar 24, 2022 at 12:45 PM Linus Torvalds > wrote: > > > > On Thu, Mar 24, 2022 at 12:41 PM syzbot > > wrote: > > > > > > syzbot has tested the proposed patch and the reproducer did not trigger any issue: > > > > Heh, well that's unfortunate. > > > > I think the issue is that it triggered a new BUG() that didn't match > > the previous NULL pointer dereference, so it thinks things are > > "fixed". > > Oh, no, it's because it used the truncated patch that didn't do anything: > > > patch: https://syzkaller.appspot.com/x/patch.diff?x=1208043d700000 > > and maybe (due to the racy nature) nothing actually happened. > It is not easy to reproduce. I'm also trying to reproduce locally. #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git 5abc1e37afa0335c52608d640fd30910b2eeda21 --00000000000099e40505db011a51 Content-Type: application/octet-stream; name="test.patch" Content-Disposition: attachment; filename="test.patch" Content-Transfer-Encoding: base64 Content-ID: X-Attachment-Id: f_l15r51s80 ZGlmZiAtLWdpdCBhL21tL2xpc3RfbHJ1LmMgYi9tbS9saXN0X2xydS5jCmluZGV4IGZjOTM4ZDhm ZjQ4Zi4uODg1YWU1ZDc3MDAyIDEwMDY0NAotLS0gYS9tbS9saXN0X2xydS5jCisrKyBiL21tL2xp c3RfbHJ1LmMKQEAgLTc2LDYgKzc2LDcgQEAgbGlzdF9scnVfZnJvbV9rbWVtKHN0cnVjdCBsaXN0 X2xydSAqbHJ1LCBpbnQgbmlkLCB2b2lkICpwdHIsCiAJc3RydWN0IGxpc3RfbHJ1X25vZGUgKm5s cnUgPSAmbHJ1LT5ub2RlW25pZF07CiAJc3RydWN0IGxpc3RfbHJ1X29uZSAqbCA9ICZubHJ1LT5s cnU7CiAJc3RydWN0IG1lbV9jZ3JvdXAgKm1lbWNnID0gTlVMTDsKKwlpbnQga21lbWNnX2lkOwog CiAJaWYgKCFscnUtPm1scnVzKQogCQlnb3RvIG91dDsKQEAgLTg0LDcgKzg1LDEyIEBAIGxpc3Rf bHJ1X2Zyb21fa21lbShzdHJ1Y3QgbGlzdF9scnUgKmxydSwgaW50IG5pZCwgdm9pZCAqcHRyLAog CWlmICghbWVtY2cpCiAJCWdvdG8gb3V0OwogCi0JbCA9IGxpc3RfbHJ1X2Zyb21fbWVtY2dfaWR4 KGxydSwgbmlkLCBtZW1jZ19jYWNoZV9pZChtZW1jZykpOworCWttZW1jZ19pZCA9IG1lbWNnX2tt ZW1faWQobWVtY2cpOworCWwgPSBsaXN0X2xydV9mcm9tX21lbWNnX2lkeChscnUsIG5pZCwga21l bWNnX2lkKTsKKwlpZiAoIWwpIHsKKwkJcHJfaW5mbygiQlVHOiB0aGUgbWVtY2coJXB4KS0+b2Jq Y2coJXB4KSwga21lbWNnX2lkOiAlZFxuIiwKKwkJCW1lbWNnLCBtZW1jZy0+b2JqY2csIGttZW1j Z19pZCk7CisJfQogb3V0OgogCWlmIChtZW1jZ19wdHIpCiAJCSptZW1jZ19wdHIgPSBtZW1jZzsK --00000000000099e40505db011a51--