Hi, i am encountering some weird behaviours in an AWS environment with a Ubuntu 18.04 instance (t3a.large). The linux kernel was updated from 5.4.0-1038-aws to 5.4.0-1039-aws and after that I receive errors when proxying connections in nginx. The setup looks like this: Requests are received via HTTPS on port 443 by nginx. These are forwarded to an AWS NLB via proxy_pass https://my-nlb; The SSL decoding there is done on the destination host. When doing many (4-5 req/s) requests through this setup, I observe that the nginx on the destination logs 499 client abort errors rather early (0.1-0.3s). On the host in question I observe that the requests to the destination get "stuck" and run into a proxy timeout after 60s. So it seems that the TCP connection between the nginx and the NLB destination breaks at some point. Over the course of 3k requests maybe 2-3 break for each of our test. I downgraded the kernel to 5.4.0-1038-aws and everything is working fine again now. The changelog for 5.4.0-1039-aws does not give me any hints what change might have caused it, and it is a bit hard for me to pin this down. How can i debug this further? I would be very greatful for any hint, thanks in advance! Some more info on the setup: cat /proc/version_signature Ubuntu 5.4.0-1039.41~18.04.1-aws 5.4.94 lspci -vnvn 00:00.0 Host bridge [0600]: Intel Corporation 440FX - 82441FX PMC [Natoma] [8086:1237] Subsystem: Amazon.com, Inc. 440FX - 82441FX PMC [Natoma] [1d0f:1237] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- SERR- TAbort- SERR- TAbort- SERR- TAbort- SERR- TAbort- SERR- TAbort- SERR-

When	Who	Action	New State
2021-03-24	Bernard Stafford	Answer	Answered
2021-03-26	Seb Mel	Reopen	Open
2021-04-08	Bernard Stafford	Answer	Answered
2021-04-08	Seb Mel	Reopen	Open
2021-04-13	gfdsf gfdsaf	Comment	Open
2021-04-24	Launchpad Janitor	Expire	Expired

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