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 AA70FC25B78 for ; Tue, 28 May 2024 20:52:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 489AB6B00A7; Tue, 28 May 2024 16:52:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 438FD6B00A8; Tue, 28 May 2024 16:52:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 34F1F6B00AA; Tue, 28 May 2024 16:52:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 176E76B00A7 for ; Tue, 28 May 2024 16:52:47 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id B35E81C047A for ; Tue, 28 May 2024 20:52:46 +0000 (UTC) X-FDA: 82169003532.12.5580E04 Received: from hannover.ccc.de (ep.leitstelle511.net [80.147.51.183]) by imf07.hostedemail.com (Postfix) with ESMTP id B3C2B40010 for ; Tue, 28 May 2024 20:52:44 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=none; spf=none (imf07.hostedemail.com: domain of ingo@hannover.ccc.de has no SPF policy when checking 80.147.51.183) smtp.mailfrom=ingo@hannover.ccc.de; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1716929565; a=rsa-sha256; cv=none; b=b8pdEjdBVkYTv+90H81mufCYYx45a61NIZw3WSe2R7h/1q2d9Q8XWhZKNqylgW7v5OVrif ZmdhTaYzaTcL4ls6qmGgeVVOXVoVx6vHQFN/IHKyTi61pndx7n9sCiynCLhJYS0q/qCUx0 vCX2FwnhgJmd6MF1lFJ1GhlPdRRY6tk= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=none; spf=none (imf07.hostedemail.com: domain of ingo@hannover.ccc.de has no SPF policy when checking 80.147.51.183) smtp.mailfrom=ingo@hannover.ccc.de; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1716929565; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rYnwabobRXy5A4vU+eI97nAXcGx6yMsrbI2Ny7oXBJg=; b=4lMBC9icIFiBlFz7kl08TX2wfXC+a2Kp/ocw3b7fOSzk2a3oFM9Jsb6cVdSp8QnRpcTcNH YHBzwhNm4vLUsAryMma2xa4lvCejGQOeXK4lLC8zhuX0T3T70KGSYBOAIuZuLDeo8FQmQB caN1uKaFPrgajHuaFzClbUw3RRU1NNY= Date: Tue, 28 May 2024 22:52:41 +0200 From: Ingo Saitz To: linux-mm@kvack.org Subject: Re: [linus:master] [mm] ba42b524a0: segfault_at_ip_sp_error Message-ID: References: <202405281425.92ece916-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <202405281425.92ece916-lkp@intel.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: B3C2B40010 X-Stat-Signature: jw1kp9rcbhmxcg7hfsmatcopye8dcbat X-HE-Tag: 1716929564-972213 X-HE-Meta: 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 dQyFv1KE EyaKkdvxSUyfB294oRoUej7DIjthf6UoPSc+vxIUI5YTDIUXgtcsPCF+YV3ws5nJIPREkS+1CN2sdeTY= 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: List-Subscribe: List-Unsubscribe: I hit the same error on devuan unstable, with startpar crashing on boot: [ 10.025881] dracut: Switching root [ 10.339687] startpar[720]: segfault at 0 ip 0000000000000000 sp 00007fffbdca9c38 error 14 likely on CPU 1 (core 0, socket 0) [ 10.340225] Code: Unable to access opcode bytes at 0xffffffffffffffd6. [ 10.349516] startpar[820]: segfault at 0 ip 0000000000000000 sp 00007ffd52c34e48 error 14 likely on CPU 3 (core 1, socket 0) [ 10.350086] Code: Unable to access opcode bytes at 0xffffffffffffffd6. Setting init_mlocked_on_free=0 on the commandline mitigates this crash and allows the system to boot successfully. I managed to get a strace of startpar here: https://hannover.ccc.de/~ingo/startpar-6.10-rc1/startpar.strace.txt.gz Complete dmesg of the boot: https://hannover.ccc.de/~ingo/startpar-6.10-rc1/dmesg-6.10-rc1.gz I'm not sure if this actually is a kernel bug or if it is a classical use after free that just got noticed by this change. Ingo -- const_cast(Λ)