Date: Mon, 28 Aug 2017 10:25:27 +0200 From: Ben RUBSON <ben.rubson@gmail.com> To: Julien Charbon <jch@freebsd.org> 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: <7B084207-062A-4529-B0DC-5BFEB6517780@gmail.com> In-Reply-To: <13DE4E6D-CE83-4B5D-BF88-0EFE65111311@gmail.com> References: <BF3A3E47-A726-49FB-B83F-666EFC5C0FF1@gmail.com> <9c306f10-7c05-d28d-e551-a930603aaafa@selasky.org> <896dd782-cb2c-0259-65d1-b00daae452de@FreeBSD.org> <0DB9F6FF-8BC9-48F5-B359-AC1905B9EB06@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>
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> On 16 Aug 2017, at 11:02, Ben RUBSON <ben.rubson@gmail.com> wrote: >=20 >> On 15 Aug 2017, at 23:33, Julien Charbon <jch@freebsd.org> wrote: >>=20 >> On 8/11/17 11:32 AM, Ben RUBSON wrote: >>>> On 08 Aug 2017, at 13:33, Julien Charbon <jch@freebsd.org> wrote: >>>>=20 >>>> On 8/8/17 10:31 AM, Hans Petter Selasky wrote: >>>>>=20 >>>>> Suggested fix attached. >>>>=20 >>>> 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. >>>=20 >>> Julien, do you plan to make this fix reach 11.0-p12 ? >>=20 >> I am checking if your issue is another flavor of the issue fixed by: >>=20 >> https://svnweb.freebsd.org/base?view=3Drevision&revision=3D307551 >> https://reviews.freebsd.org/D8211 >>=20 >> 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. >>=20 >> Thus could you try to apply this patch: >>=20 >> = https://github.com/freebsd/freebsd/commit/acb5bfda99b753d9ead3529d04f20087= c5f7d0a0.patch >>=20 >> and see if you can still reproduce this issue? >=20 > 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. >=20 > If other network stack experts (I'm not) agree with your analysis, > we could then certainly go further with D8211 / r307551. >=20 > One thing that perhaps might help : > # netstat -an | grep TIME_WAIT$ | wc -l > 468 >=20 > 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... >=20 > Number of TIME_WAIT connections however does not decrease, but = increases. >=20 >> 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. >=20 > 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") 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. Thank you very much ! Ben
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