From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id 118836B0003 for ; Sat, 13 Oct 2018 09:00:37 -0400 (EDT) Received: by mail-ed1-f69.google.com with SMTP id e7-v6so8686638edb.23 for ; Sat, 13 Oct 2018 06:00:37 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id x7-v6si3764341edx.76.2018.10.13.06.00.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 13 Oct 2018 06:00:34 -0700 (PDT) Subject: Re: [Bug 201377] New: Kernel BUG under memory pressure: unable to handle kernel NULL pointer dereference at 00000000000000f0 References: <20181012155533.2f15a8bb35103aa1fa87962e@linux-foundation.org> <20181012155641.b3a1610b4ddcd37e374115d4@linux-foundation.org> From: Vlastimil Babka Message-ID: <9f77da23-2a46-29a5-6aa7-fe9e7cca1056@suse.cz> Date: Sat, 13 Oct 2018 14:57:50 +0200 MIME-Version: 1.0 In-Reply-To: <20181012155641.b3a1610b4ddcd37e374115d4@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , bugzilla-daemon@bugzilla.kernel.org, leozinho29_eu@hotmail.com Cc: linux-mm@kvack.org, Greg Kroah-Hartman On 10/13/18 12:56 AM, Andrew Morton wrote: > (cc linux-mm, argh) > > On Fri, 12 Oct 2018 15:55:33 -0700 Andrew Morton wrote: > >> >> (switched to email. Please respond via emailed reply-to-all, not via the >> bugzilla web interface). >> >> Vlastimil, it looks like your August 21 smaps changes are failing. >> This one is pretty urgent, please. Thanks, will look in few hours. Glad that there will be rc8... >> Leonardo (yes?): thanks for reporting. Very helpful. >> >> On Thu, 11 Oct 2018 18:13:31 +0000 bugzilla-daemon@bugzilla.kernel.org wrote: >> >>> https://bugzilla.kernel.org/show_bug.cgi?id=201377 >>> >>> Bug ID: 201377 >>> Summary: Kernel BUG under memory pressure: unable to handle >>> kernel NULL pointer dereference at 00000000000000f0 >>> Product: Memory Management >>> Version: 2.5 >>> Kernel Version: 4.19-rc7 >>> Hardware: All >>> OS: Linux >>> Tree: Mainline >>> Status: NEW >>> Severity: normal >>> Priority: P1 >>> Component: Other >>> Assignee: akpm@linux-foundation.org >>> Reporter: leozinho29_eu@hotmail.com >>> Regression: No >>> >>> Created attachment 278997 >>> --> https://bugzilla.kernel.org/attachment.cgi?id=278997&action=edit >>> dmesg and kernel config >>> >>> I'm using Xubuntu 18.04 and I noticed that under memory pressure the script >>> from https://github.com/pixelb/ps_mem.git (HEAD >>> 1ed0bc5519d889d58235f2c35db01e4ede0d8231is) causing a kernel BUG and locking a >>> CPU. On dmesg the following appears: >>> >>> BUG: unable to handle kernel NULL pointer dereference at 00000000000000f0 >>> >>> After this BUG the computer performance becomes greatly degraded, some software >>> do not close, some fail to open, some fail to work properly. As an example, >>> bash fails to autocomplete. >>> >>> Steps to reproduce: >>> >>> 1) Be under memory pressure. Using dd to write a large file at /dev/shm works >>> for this; >>> 2) Run the script from https://github.com/pixelb/ps_mem.git >>> >>> Expected result: script will print information and system will keep working >>> normally; >>> >>> Observed result: script is killed, kernel BUG happens, CPU get stuck and >>> computer presents problems. >>> >>> I did not observe this with 4.17.19, I'll bisect and see if I can find which >>> commit is causing this. >>> >>> I'm sorry if I'm reporting to the wrong product and component. >>> >>> -- >>> You are receiving this mail because: >>> You are the assignee for the bug.