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 A2D76C54E41 for ; Tue, 5 Mar 2024 13:03:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1B5116B00D2; Tue, 5 Mar 2024 08:03:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 165976B00D3; Tue, 5 Mar 2024 08:03:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05419940007; Tue, 5 Mar 2024 08:03:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id E5EDB6B00D2 for ; Tue, 5 Mar 2024 08:03:16 -0500 (EST) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id BD229A0DC6 for ; Tue, 5 Mar 2024 13:03:16 +0000 (UTC) X-FDA: 81863001192.07.E167482 Received: from mail-oi1-f175.google.com (mail-oi1-f175.google.com [209.85.167.175]) by imf21.hostedemail.com (Postfix) with ESMTP id 16A5E1C001F for ; Tue, 5 Mar 2024 13:03:13 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=bHGsv8Qi; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf21.hostedemail.com: domain of elver@google.com designates 209.85.167.175 as permitted sender) smtp.mailfrom=elver@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1709643794; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Y03NzawgLsuvVK3dnh3vUuU8cb8xlgzFX71BC6/j7b8=; b=h3LEus+tZaze2t2dntAu+WHlM+VC7/fXo0xYwRllTUC1vyd4s4xW45dwIaviydOgeYZ09g 83XNf2AvHN5cjWQ5LilUI1cELZ0GZ8R5MALS1E5TZmTyMOlX7qa8UCmq4jyY49cPU8G0OA 3pvp0Aq+JVQSZ/vY6FQ+ccdyER2jYho= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=bHGsv8Qi; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf21.hostedemail.com: domain of elver@google.com designates 209.85.167.175 as permitted sender) smtp.mailfrom=elver@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1709643794; a=rsa-sha256; cv=none; b=IJGbLxz6qzlbFQhJbnSlOYBg8YKw+SlfrTakQzBU6XvzKuaeDtFL+T0MZrCvicfQOXBpT6 VcKJRrBWuBDl0bNgvB+cxaUj3S96IgwwL6kH0e9OpzBZw3+3D4m4I9sPPrQpQSAY/M2IW1 JVgUPh80+VE/ZmEtVH5waLdEGqpxqNg= Received: by mail-oi1-f175.google.com with SMTP id 5614622812f47-3c1a7d51fb5so4121408b6e.1 for ; Tue, 05 Mar 2024 05:03:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1709643793; x=1710248593; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=Y03NzawgLsuvVK3dnh3vUuU8cb8xlgzFX71BC6/j7b8=; b=bHGsv8QiuC/kUVGkcULDJesjrpPnKNVSYcr+crzJ35DSbUZMsoAKfqEbY731IY2WCt HGwWW79Qn9dUoCwtn/3CzMSCXNS3Syl3g2NnaMMzfAJMfyr3cpmVl/16GWEZsyOtWs3G HwnQARq/7m/YJxzXKaccmpyJA5wSEzFzIWKuZfsGmdlb0MS0bzzI4caV8jxbeeY29WG2 anL0Mf86sc4VRZVR2tW4lnDlwOStAVF1qaZQ2E0vdWkfIGDo2MeTvwhKMvFcgiF+9XzA YdXLyavN64CQK0IXBA3YP8TdvcEZp+6MUG2nHUEiXDnuJyO7eqFZRjhs32XwY78RMeIx pfpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709643793; x=1710248593; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Y03NzawgLsuvVK3dnh3vUuU8cb8xlgzFX71BC6/j7b8=; b=sXIYebyU5eiauB6NGgfXVLgliLCwIpsWc0rW1VViJZkdbA55/kD7wS1OmdHAWYNdw3 B5V0B5gdSybARLGbOPjuXpbHQoideKO7z1fScmdJO0PpmoQNS/nrUxXWXHp2q/Ea9W+F UzhFxS+xVVRw2muWcOcY942wzJvQ0dy3s8LiliLSRVwRSd5S8vYegtyQKxNJZgniTnGt PWezb4gm9eim6tCNInsOhBJ1jWAzp25kTxG593pOo7nX8rbqAL+JCW0epe3ztyubxssG EfU5a0HXBKvJvZnaCQUJwnKwMS6W4OPrToupfFRoV3h6HTpLGLiEg3FBL25Wcd4jQSAm 8hmg== X-Forwarded-Encrypted: i=1; AJvYcCUHnwE7Bs3+t1b6E7mfnozL7niahwIGWzpCE1sqweHX0oXy6ey/vZjHNlvFaiYtO9XIbgWQohVzlwoNQcue6tn3zHA= X-Gm-Message-State: AOJu0Yz5MAdSOOImhIPztDRa/1DPZefmPqxU+nFhXbzwYMspqlQJ6UBd Av3VFjXXAziw4CAVDHm/uS8oZ2rwsXtZd3PXwj9bFYe6CiquBByHXR1dm30AiOoyNe6eb+eCWhj mACBfhaRFYWmKiQ/mmA7dWTfTn+gjI4Mmi3st X-Google-Smtp-Source: AGHT+IEjB+D36pPsTT+GfJa0+YlKEbqMGVHKFQ8yEGj0UDz27soUzs9SaKjQOp1hKs2S/ESVzH4SX6uDdxrplqFQxuw= X-Received: by 2002:a05:6808:1597:b0:3c1:ae52:6f91 with SMTP id t23-20020a056808159700b003c1ae526f91mr1799803oiw.58.1709643792910; Tue, 05 Mar 2024 05:03:12 -0800 (PST) MIME-Version: 1.0 References: <202403051032.e2f865a-lkp@intel.com> In-Reply-To: From: Marco Elver Date: Tue, 5 Mar 2024 14:02:35 +0100 Message-ID: Subject: Re: [linux-next:master] [mm,page_owner] 4bedfb314b: BUG:KASAN:null-ptr-deref_in_init_page_owner To: Oscar Salvador Cc: kernel test robot , oe-lkp@lists.linux.dev, lkp@intel.com, Linux Memory Management List , Andrew Morton , Vlastimil Babka , Andrey Konovalov , Alexander Potapenko , Michal Hocko , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Stat-Signature: z5r788whzjm5e7mtdeiek8455cct7f3r X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 16A5E1C001F X-HE-Tag: 1709643793-51691 X-HE-Meta: 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 xnA+I8Pu u/B8UiDNi9hrwaoZ8Om7vVfJuTCbh2bwzL9st/J4ymaJxK44= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000134, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 5 Mar 2024 at 10:26, Oscar Salvador wrote: > > On Tue, Mar 05, 2024 at 02:08:23PM +0800, kernel test robot wrote: > > > > [ 6.582562][ T0] Node 0, zone DMA32: page owner found early allocated 0 pages > > [ 6.612136][ T0] Node 0, zone Normal: page owner found early allocated 73871 pages > > [ 6.612762][ T0] ================================================================== > > [ 6.613351][ T0] BUG: KASAN: null-ptr-deref in init_page_owner (arch/x86/include/asm/atomic.h:28) > > [ 6.613893][ T0] Write of size 4 at addr 000000000000001c by task swapper/0 > > [ 6.614434][ T0] > > [ 6.614600][ T0] CPU: 0 PID: 0 Comm: swapper Tainted: G T 6.8.0-rc5-00256-g4bedfb314bdd #1 29e70169ace75ef72d53825e983f3dcb1d5756d9 > > [ 6.615605][ T0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 > > [ 6.616367][ T0] Call Trace: > > [ 6.616604][ T0] > > [ 6.616816][ T0] ? dump_stack_lvl (lib/dump_stack.c:?) > > [ 6.617161][ T0] ? print_report (mm/kasan/report.c:?) > > [ 6.617499][ T0] ? init_page_owner (arch/x86/include/asm/atomic.h:28) > > So, we are crashing here: > > /* Initialize dummy and failure stacks and link them to stack_list */ > dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle); > failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle); > refcount_set(&dummy_stack.stack_record->count, 1); > refcount_set(&failure_stack.stack_record->count, 1); > > when trying to set the refcount. Allegedly, because dummy_handle is 0. > I thought we fixed that with > > commit 3ee34eabac2abb6b1b6fcdebffe18870719ad000 > Author: Oscar Salvador > Date: Thu Feb 15 22:59:01 2024 +0100 > > lib/stackdepot: fix first entry having a 0-handle > > > But I guess this is different. > The obvious way out is to only set the refcount and link the stacks > if their handles are not 0. > > Marco, could it be that stackdepot was too overloaded, that by the time > page_owner gets initialized, there are no more space for its stacks, and > hence return 0-handles?. That's possible. But it's unclear to me what exactly happens. Are you able to reproduce the issue? (I haven't been able to because the config enables CFI which seems to cause other issues for me, presumably toolchain related. :-/ )