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Wed, 04 May 2022 11:31:26 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzA9Ji+G5KCYEXFnDpZIK3Bup0w0RF0Z/dspcO6sxnccRhu0add6ZvdZkW3XyEfR9yWmA1uGw== X-Received: by 2002:a17:903:41c3:b0:15e:b690:bedc with SMTP id u3-20020a17090341c300b0015eb690bedcmr9689615ple.161.1651689086262; Wed, 04 May 2022 11:31:26 -0700 (PDT) Received: from [10.10.69.234] ([8.34.116.185]) by smtp.gmail.com with ESMTPSA id m17-20020aa78a11000000b0050dc76281d6sm8852386pfa.176.2022.05.04.11.31.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 May 2022 11:31:24 -0700 (PDT) Message-ID: <15f5f8d6-dc92-d491-d455-dd6b22b34bc3@redhat.com> Date: Wed, 4 May 2022 20:31:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v8 23/70] mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap() To: Janosch Frank , Liam Howlett , Heiko Carstens Cc: Claudio Imbrenda , Andrew Morton , Guenter Roeck , "maple-tree@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Yu Zhao , Juergen Gross , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Andreas Krebbel , Ilya Leoshkevich , Thomas Huth References: <20220426150616.3937571-24-Liam.Howlett@oracle.com> <20220428201947.GA1912192@roeck-us.net> <20220429003841.cx7uenepca22qbdl@revolver> <20220428181621.636487e753422ad0faf09bd6@linux-foundation.org> <20220502001358.s2azy37zcc27vgdb@revolver> <20220501172412.50268e7b217d0963293e7314@linux-foundation.org> <20220502133050.kuy2kjkzv6msokeb@revolver> <20220503215520.qpaukvjq55o7qwu3@revolver> <60a3bc3f-5cd6-79ac-a7a8-4ecc3d7fd3db@linux.ibm.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <60a3bc3f-5cd6-79ac-a7a8-4ecc3d7fd3db@linux.ibm.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8858EC0081 X-Stat-Signature: cq4ifdqkitajfiut1wz8he8cbgnr9gf3 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=E5e0lu3I; spf=none (imf10.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1651689073-349458 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 04.05.22 09:37, Janosch Frank wrote: > On 5/3/22 23:55, Liam Howlett wrote: >> * Heiko Carstens [220503 15:49]: >>> On Mon, May 02, 2022 at 08:50:04PM +0200, Heiko Carstens wrote: >>>> On Mon, May 02, 2022 at 01:31:00PM +0000, Liam Howlett wrote: >>>>> * Heiko Carstens [220502 06:18]: >>>>>> On Sun, May 01, 2022 at 05:24:12PM -0700, Andrew Morton wrote: >>>>>>> (cc S390 maintainers) >>>>>>> (cc stable & Greg) >>> ... >>>>>>>> booting. The last thing I see is: >>>>>>>> >>>>>>>> "[ 4.668916] Spectre V2 mitigation: execute trampolines" >>>>>>>> >>>>>>>> I've bisected back to commit e553f62f10d9 (mm, page_alloc: fix >>>>>>>> build_zonerefs_node()) >>>>>>>> >>>>>>>> With the this commit, I am unable to boot one out of three times. When >>>>>>>> using the previous commit I was not able to get it to hang after trying >>>>>>>> 10+ times. This is a qemu s390 install with KASAN on and I see no error >>>>>>>> messages. I think it's likely it is this patch, but no guaranteed. >>> ... >>>>>> Liam, could you share your kernel config? >>>>> >>>>> Sure thing. See attached. >>>> >>>> So, I can reproduce the hanging system now. However this looks like a >>>> qemu problem on s390, since I can reproduce this only with Qemu+TCG. >>>> Qemu with kvm works without any problems (same if I use z/VM as >>>> hypervisor). >>>> >>>> Janosch, Claudio, can you have a look at this please? >>> >>> So, at least for me this problem also exists with plain v5.17. >>> Switching off KASAN, or alternatively switching to KASAN_INLINE >>> "fixes" it for me with Qemu+TCG. >>> >>> Liam, could you please also try to disable KASAN in your config? With >>> that I think we can be almost sure this could be some bug in Qemu. >> >> With KASAN, my tree fails 100% of the time (mm-stable + my maple tree >> patches) >> >> Without KASAN, it boots 100% of the time. >> >> I think this verifies with you say above? >> >> Thanks, >> Liam > > I had a short look yesterday and the boot usually hangs in the raid6 > code. Disabling vector instructions didn't make a difference but a few > interruptions via GDB solve the problem for some reason. > > CCing David and Thomas for TCG > I somehow recall that KASAN was always disabled under TCG, I might be wrong (I thought we'd get a message early during boot that the HW doesn't support KASAN). I recall that raid code is a heavy user of vector instructions. How can I reproduce? Compile upstream (or -next?) with kasan support and run it under TCG? -- Thanks, David / dhildenb