Date: Mon, 28 Aug 2017 11:27:15 +0200 From: Julien Charbon <jch@freebsd.org> To: Ben RUBSON <ben.rubson@gmail.com> Cc: Hans Petter Selasky <hps@selasky.org>, FreeBSD Net <freebsd-net@freebsd.org>, hiren <hiren@strugglingcoder.info>, Slawa Olhovchenkov <slw@zxy.spb.ru>, FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: mlx4en, timer irq @100%... (11.0 stuck on high network load ???) Message-ID: <82e661b4-1bac-ff5b-f776-8dba44cac15e@freebsd.org> In-Reply-To: <7B084207-062A-4529-B0DC-5BFEB6517780@gmail.com> References: <BF3A3E47-A726-49FB-B83F-666EFC5C0FF1@gmail.com> <7f14c95d-1ef8-bf82-c469-e6566c3aba66@selasky.org> <76A5EE7E-1D2E-46B4-86F1-F219C3DCE6EA@gmail.com> <e6f9df1c-8b55-8a3b-9f44-e67c26561543@selasky.org> <4C91C6E5-0725-42E7-9813-1F3ACF3DDD6E@gmail.com> <5840c25e-7472-3276-6df9-1ed4183078ad@selasky.org> <2ADA8C57-2C2D-4F97-9F0B-82D53EDDC649@gmail.com> <061cdf72-6285-8239-5380-58d9d19a1ef7@selasky.org> <92BEE83D-498F-47D5-A53C-39DCDC00A0FD@gmail.com> <5d8960d8-e1ff-8719-320f-d3ae84054714@selasky.org> <6B4A35F7-5694-4945-9575-19ADB678F9FA@gmail.com> <297a784a-3d80-b1a6-652e-a78621fe5a8b@selasky.org> <3ECCFBF1-18D9-4E33-8F39-0C366C3BB8B4@gmail.com> <c05c2b1c-b5a8-c39c-6dff-e6cc0d8642bf@selasky.org> <0a5787c5-8a53-ab09-971a-dc1cd5f3aca0@freebsd.org> <E4124973-5F01-4EAF-AAF3-F32F419678A4@gmail.com> <645f2ee3-3eaa-660e-2a64-37d53e88322f@freebsd.org> <13DE4E6D-CE83-4B5D-BF88-0EFE65111311@gmail.com> <7B084207-062A-4529-B0DC-5BFEB6517780@gmail.com>
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Hi Ben, On 8/28/17 10:25 AM, Ben RUBSON wrote: >> On 16 Aug 2017, at 11:02, Ben RUBSON <ben.rubson@gmail.com> wrote: >> >>> On 15 Aug 2017, at 23:33, Julien Charbon <jch@freebsd.org> wrote: >>> >>> On 8/11/17 11:32 AM, Ben RUBSON wrote: >>>>> On 08 Aug 2017, at 13:33, Julien Charbon <jch@freebsd.org> wrote: >>>>> >>>>> On 8/8/17 10:31 AM, Hans Petter Selasky wrote: >>>>>> >>>>>> Suggested fix attached. >>>>> >>>>> I agree we your conclusion. Just for the record, more precisely this >>>>> regression seems to have been introduced with: >>>>> (...) >>>>> Thus good catch, and your patch looks good. I am going to just verify >>>>> the other in_pcbrele_wlocked() calls in TCP stack. >>>> >>>> Julien, do you plan to make this fix reach 11.0-p12 ? >>> >>> I am checking if your issue is another flavor of the issue fixed by: >>> >>> https://svnweb.freebsd.org/base?view=revision&revision=307551 >>> https://reviews.freebsd.org/D8211 >>> >>> This fix in not in 11.0 but in 11.1. Currently I did not found how an >>> inp in INP_TIMEWAIT state can have been INP_FREED without having its tw >>> set to NULL already except the issue fixed by r307551. >>> >>> Thus could you try to apply this patch: >>> >>> https://github.com/freebsd/freebsd/commit/acb5bfda99b753d9ead3529d04f20087c5f7d0a0.patch >>> >>> and see if you can still reproduce this issue? >> >> Thank you for your answer Julien. >> Unfortunately, I'm not sure at all how to reproduce the issue. >> I have other servers which are 100% identical to this one, same workload, >> same some-months uptime, but they did not trigger the bug yet. >> >> If other network stack experts (I'm not) agree with your analysis, >> we could then certainly go further with D8211 / r307551. >> >> One thing that perhaps might help : >> # netstat -an | grep TIME_WAIT$ | wc -l >> 468 >> >> Note that due to this running bug, sendmail has lots of difficulties to send outgoing mails. >> As soon as I run the above netstat command, I receive a lot of stacked mails (more than 20 this time). >> As if netstat was able to somehow help... >> >> Number of TIME_WAIT connections however does not decrease, but increases. >> >>> And in the spirit of r307551 fix and based on Hans patch I will also >>> propose to add a kernel log describing the issue instead of starting an >>> infinite loop when INVARIANT is not set. >> >> Which should then never be triggered :) >> Good idea I think ! > > What about : > D8211/r307551 > + Hans' patch > + Julien's idea of a kernel log (sort of "We should not be here but we are") I did this change and I am testing it, on your side did you try this patch applied on 11.0? https://github.com/freebsd/freebsd/commit/acb5bfda99b753d9ead3529d04f20087c5f7d0a0.patch > And backporting all this to 11.0 (and so to 11.1 too) ? > > As this bug can impact every FreeBSD machine / server, > leading to an unavailable / unreachable system (this is how mine ended), > sounds like it could inevitably be a good thing, for production stability purpose. The main fix for your issue is (I believe): Fix a double-free when an inp transitions to INP_TIMEWAIT state after having been dropped. https://svnweb.freebsd.org/base?view=revision&revision=307551 This fix has been MFC-ed on both stable/11, stable/10 and is already included in 11.1 and will be in 10.4. To push in 11.0 release directly, I guess you have to promote this change to an Errata (never did that myself): https://www.freebsd.org/security/notices.html https://www.freebsd.org/security/security.html#reporting While waiting for this errata to be accepted better using the patch. My 2 cents. -- Julien
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