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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 7 Feb 2020 08:13:16 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 0178DF7552691044 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Feb 2020 08:13:15 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 608CEA405B; Fri, 7 Feb 2020 08:13:15 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 18503A4054; Fri, 7 Feb 2020 08:13:15 +0000 (GMT) Received: from oc7455500831.ibm.com (unknown [9.152.224.61]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 7 Feb 2020 08:13:15 +0000 (GMT) Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot To: "Michael S. Tsirkin" Cc: eperezma@redhat.com, "virtualization@lists.linux-foundation.org" , Stephen Rothwell , Linux Next Mailing List , "linux-kernel@vger.kernel.org" , kvm list , Halil Pasic , Cornelia Huck References: <20200107042401-mutt-send-email-mst@kernel.org> <20200107065434-mutt-send-email-mst@kernel.org> <20200120012724-mutt-send-email-mst@kernel.org> <2a63b15f-8cf5-5868-550c-42e2cfd92c60@de.ibm.com> <1ade56b5-083f-bb6f-d3e0-3ddcf78f4d26@de.ibm.com> <20200206171349-mutt-send-email-mst@kernel.org> <5c860fa1-cef5-b389-4ebf-99a62afa0fe8@de.ibm.com> <20200207025806-mutt-send-email-mst@kernel.org> From: Christian Borntraeger Autocrypt: addr=borntraeger@de.ibm.com; prefer-encrypt=mutual; keydata= xsFNBE6cPPgBEAC2VpALY0UJjGmgAmavkL/iAdqul2/F9ONz42K6NrwmT+SI9CylKHIX+fdf J34pLNJDmDVEdeb+brtpwC9JEZOLVE0nb+SR83CsAINJYKG3V1b3Kfs0hydseYKsBYqJTN2j CmUXDYq9J7uOyQQ7TNVoQejmpp5ifR4EzwIFfmYDekxRVZDJygD0wL/EzUr8Je3/j548NLyL 4Uhv6CIPf3TY3/aLVKXdxz/ntbLgMcfZsDoHgDk3lY3r1iwbWwEM2+eYRdSZaR4VD+JRD7p8 0FBadNwWnBce1fmQp3EklodGi5y7TNZ/CKdJ+jRPAAnw7SINhSd7PhJMruDAJaUlbYaIm23A +82g+IGe4z9tRGQ9TAflezVMhT5J3ccu6cpIjjvwDlbxucSmtVi5VtPAMTLmfjYp7VY2Tgr+ T92v7+V96jAfE3Zy2nq52e8RDdUo/F6faxcumdl+aLhhKLXgrozpoe2nL0Nyc2uqFjkjwXXI OBQiaqGeWtxeKJP+O8MIpjyGuHUGzvjNx5S/592TQO3phpT5IFWfMgbu4OreZ9yekDhf7Cvn /fkYsiLDz9W6Clihd/xlpm79+jlhm4E3xBPiQOPCZowmHjx57mXVAypOP2Eu+i2nyQrkapaY IdisDQfWPdNeHNOiPnPS3+GhVlPcqSJAIWnuO7Ofw1ZVOyg/jwARAQABzUNDaHJpc3RpYW4g Qm9ybnRyYWVnZXIgKDJuZCBJQk0gYWRkcmVzcykgPGJvcm50cmFlZ2VyQGxpbnV4LmlibS5j b20+wsF5BBMBAgAjBQJdP/hMAhsDBwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQEXu8 gLWmHHy/pA/+JHjpEnd01A0CCyfVnb5fmcOlQ0LdmoKWLWPvU840q65HycCBFTt6V62cDljB kXFFxMNA4y/2wqU0H5/CiL963y3gWIiJsZa4ent+KrHl5GK1nIgbbesfJyA7JqlB0w/E/SuY NRQwIWOo/uEvOgXnk/7+rtvBzNaPGoGiiV1LZzeaxBVWrqLtmdi1iulW/0X/AlQPuF9dD1Px hx+0mPjZ8ClLpdSp5d0yfpwgHtM1B7KMuQPQZGFKMXXTUd3ceBUGGczsgIMipZWJukqMJiJj QIMH0IN7XYErEnhf0GCxJ3xAn/J7iFpPFv8sFZTvukntJXSUssONnwiKuld6ttUaFhSuSoQg OFYR5v7pOfinM0FcScPKTkrRsB5iUvpdthLq5qgwdQjmyINt3cb+5aSvBX2nNN135oGOtlb5 tf4dh00kUR8XFHRrFxXx4Dbaw4PKgV3QLIHKEENlqnthH5t0tahDygQPnSucuXbVQEcDZaL9 WgJqlRAAj0pG8M6JNU5+2ftTFXoTcoIUbb0KTOibaO9zHVeGegwAvPLLNlKHiHXcgLX1tkjC DrvE2Z0e2/4q7wgZgn1kbvz7ZHQZB76OM2mjkFu7QNHlRJ2VXJA8tMXyTgBX6kq1cYMmd/Hl OhFrAU3QO1SjCsXA2CDk9MM1471mYB3CTXQuKzXckJnxHkHOwU0ETpw8+AEQAJjyNXvMQdJN t07BIPDtbAQk15FfB0hKuyZVs+0lsjPKBZCamAAexNRk11eVGXK/YrqwjChkk60rt3q5i42u PpNMO9aS8cLPOfVft89Y654Qd3Rs1WRFIQq9xLjdLfHh0i0jMq5Ty+aiddSXpZ7oU6E+ud+X Czs3k5RAnOdW6eV3+v10sUjEGiFNZwzN9Udd6PfKET0J70qjnpY3NuWn5Sp1ZEn6lkq2Zm+G 9G3FlBRVClT30OWeiRHCYB6e6j1x1u/rSU4JiNYjPwSJA8EPKnt1s/Eeq37qXXvk+9DYiHdT PcOa3aNCSbIygD3jyjkg6EV9ZLHibE2R/PMMid9FrqhKh/cwcYn9FrT0FE48/2IBW5mfDpAd YvpawQlRz3XJr2rYZJwMUm1y+49+1ZmDclaF3s9dcz2JvuywNq78z/VsUfGz4Sbxy4ShpNpG REojRcz/xOK+FqNuBk+HoWKw6OxgRzfNleDvScVmbY6cQQZfGx/T7xlgZjl5Mu/2z+ofeoxb vWWM1YCJAT91GFvj29Wvm8OAPN/+SJj8LQazd9uGzVMTz6lFjVtH7YkeW/NZrP6znAwv5P1a DdQfiB5F63AX++NlTiyA+GD/ggfRl68LheSskOcxDwgI5TqmaKtX1/8RkrLpnzO3evzkfJb1 D5qh3wM1t7PZ+JWTluSX8W25ABEBAAHCwV8EGAECAAkFAk6cPPgCGwwACgkQEXu8gLWmHHz8 2w//VjRlX+tKF3szc0lQi4X0t+pf88uIsvR/a1GRZpppQbn1jgE44hgF559K6/yYemcvTR7r 6Xt7cjWGS4wfaR0+pkWV+2dbw8Xi4DI07/fN00NoVEpYUUnOnupBgychtVpxkGqsplJZQpng v6fauZtyEcUK3dLJH3TdVQDLbUcL4qZpzHbsuUnTWsmNmG4Vi0NsEt1xyd/Wuw+0kM/oFEH1 4BN6X9xZcG8GYUbVUd8+bmio8ao8m0tzo4pseDZFo4ncDmlFWU6hHnAVfkAs4tqA6/fl7RLN JuWBiOL/mP5B6HDQT9JsnaRdzqF73FnU2+WrZPjinHPLeE74istVgjbowvsgUqtzjPIG5pOj cAsKoR0M1womzJVRfYauWhYiW/KeECklci4TPBDNx7YhahSUlexfoftltJA8swRshNA/M90/ i9zDo9ySSZHwsGxG06ZOH5/MzG6HpLja7g8NTgA0TD5YaFm/oOnsQVsf2DeAGPS2xNirmknD jaqYefx7yQ7FJXXETd2uVURiDeNEFhVZWb5CiBJM5c6qQMhmkS4VyT7/+raaEGgkEKEgHOWf ZDP8BHfXtszHqI3Fo1F4IKFo/AP8GOFFxMRgbvlAs8z/+rEEaQYjxYJqj08raw6P4LFBqozr nS4h0HDFPrrp1C2EMVYIQrMokWvlFZbCpsdYbBI= Date: Fri, 7 Feb 2020 09:13:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20200207025806-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 20020708-0012-0000-0000-000003849033 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20020708-0013-0000-0000-000021C1008C Message-Id: <97c93d38-ef07-e321-d133-18483d54c0c0@de.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-06_04:2020-02-06,2020-02-06 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 mlxlogscore=999 clxscore=1015 suspectscore=0 lowpriorityscore=0 adultscore=0 malwarescore=0 impostorscore=0 phishscore=0 mlxscore=0 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002070062 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07.02.20 08:58, Michael S. Tsirkin wrote: > On Fri, Feb 07, 2020 at 08:47:14AM +0100, Christian Borntraeger wrote: >> Also adding Cornelia. >> >> >> On 06.02.20 23:17, Michael S. Tsirkin wrote: >>> On Thu, Feb 06, 2020 at 04:12:21PM +0100, Christian Borntraeger wrote: >>>> >>>> >>>> On 06.02.20 15:22, eperezma@redhat.com wrote: >>>>> Hi Christian. >>>>> >>>>> Could you try this patch on top of ("38ced0208491 vhost: use batched version by default")? >>>>> >>>>> It will not solve your first random crash but it should help with the lost of network connectivity. >>>>> >>>>> Please let me know how does it goes. >>>> >>>> >>>> 38ced0208491 + this seem to be ok. >>>> >>>> Not sure if you can make out anything of this (and the previous git bisect log) >>> >>> Yes it does - that this is just bad split-up of patches, and there's >>> still a real bug that caused worse crashes :) >>> >>> So I just pushed batch-v4. >>> I expect that will fail, and bisect to give us >>> vhost: batching fetches >>> Can you try that please? >>> >> >> yes. >> >> eccb852f1fe6bede630e2e4f1a121a81e34354ab is the first bad commit >> commit eccb852f1fe6bede630e2e4f1a121a81e34354ab >> Author: Michael S. Tsirkin >> Date: Mon Oct 7 06:11:18 2019 -0400 >> >> vhost: batching fetches >> >> With this patch applied, new and old code perform identically. >> >> Lots of extra optimizations are now possible, e.g. >> we can fetch multiple heads with copy_from/to_user now. >> We can get rid of maintaining the log array. Etc etc. >> >> Signed-off-by: Michael S. Tsirkin >> >> drivers/vhost/test.c | 2 +- >> drivers/vhost/vhost.c | 39 ++++++++++++++++++++++++++++++++++----- >> drivers/vhost/vhost.h | 4 +++- >> 3 files changed, 38 insertions(+), 7 deletions(-) >> > > > And the symptom is still the same - random crashes > after a bit of traffic, right? random guest crashes after a reboot of the guests. As if vhost would still write into now stale buffers. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot Date: Fri, 7 Feb 2020 09:13:14 +0100 Message-ID: <97c93d38-ef07-e321-d133-18483d54c0c0@de.ibm.com> References: <20200107042401-mutt-send-email-mst@kernel.org> <20200107065434-mutt-send-email-mst@kernel.org> <20200120012724-mutt-send-email-mst@kernel.org> <2a63b15f-8cf5-5868-550c-42e2cfd92c60@de.ibm.com> <1ade56b5-083f-bb6f-d3e0-3ddcf78f4d26@de.ibm.com> <20200206171349-mutt-send-email-mst@kernel.org> <5c860fa1-cef5-b389-4ebf-99a62afa0fe8@de.ibm.com> <20200207025806-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200207025806-mutt-send-email-mst@kernel.org> Content-Language: en-US Sender: kvm-owner@vger.kernel.org To: "Michael S. Tsirkin" Cc: eperezma@redhat.com, "virtualization@lists.linux-foundation.org" , Stephen Rothwell , Linux Next Mailing List , "linux-kernel@vger.kernel.org" , kvm list , Halil Pasic , Cornelia Huck List-Id: virtualization@lists.linuxfoundation.org On 07.02.20 08:58, Michael S. Tsirkin wrote: > On Fri, Feb 07, 2020 at 08:47:14AM +0100, Christian Borntraeger wrote: >> Also adding Cornelia. >> >> >> On 06.02.20 23:17, Michael S. Tsirkin wrote: >>> On Thu, Feb 06, 2020 at 04:12:21PM +0100, Christian Borntraeger wrote: >>>> >>>> >>>> On 06.02.20 15:22, eperezma@redhat.com wrote: >>>>> Hi Christian. >>>>> >>>>> Could you try this patch on top of ("38ced0208491 vhost: use batched version by default")? >>>>> >>>>> It will not solve your first random crash but it should help with the lost of network connectivity. >>>>> >>>>> Please let me know how does it goes. >>>> >>>> >>>> 38ced0208491 + this seem to be ok. >>>> >>>> Not sure if you can make out anything of this (and the previous git bisect log) >>> >>> Yes it does - that this is just bad split-up of patches, and there's >>> still a real bug that caused worse crashes :) >>> >>> So I just pushed batch-v4. >>> I expect that will fail, and bisect to give us >>> vhost: batching fetches >>> Can you try that please? >>> >> >> yes. >> >> eccb852f1fe6bede630e2e4f1a121a81e34354ab is the first bad commit >> commit eccb852f1fe6bede630e2e4f1a121a81e34354ab >> Author: Michael S. Tsirkin >> Date: Mon Oct 7 06:11:18 2019 -0400 >> >> vhost: batching fetches >> >> With this patch applied, new and old code perform identically. >> >> Lots of extra optimizations are now possible, e.g. >> we can fetch multiple heads with copy_from/to_user now. >> We can get rid of maintaining the log array. Etc etc. >> >> Signed-off-by: Michael S. Tsirkin >> >> drivers/vhost/test.c | 2 +- >> drivers/vhost/vhost.c | 39 ++++++++++++++++++++++++++++++++++----- >> drivers/vhost/vhost.h | 4 +++- >> 3 files changed, 38 insertions(+), 7 deletions(-) >> > > > And the symptom is still the same - random crashes > after a bit of traffic, right? random guest crashes after a reboot of the guests. As if vhost would still write into now stale buffers.