Bug 1217502 - Data of an ACKed tcp segment does not reach user space
Summary: Data of an ACKed tcp segment does not reach user space
Status: NEW
Alias: None
Product: openSUSE Tumbleweed
Classification: openSUSE
Component: Kernel:Networking (show other bugs)
Version: Current
Hardware: Other Other
: P5 - None : Normal (vote)
Target Milestone: ---
Assignee: Kernel Bugs
QA Contact: E-mail List
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Reported: 2023-11-26 17:12 UTC by Marcus Hüwe
Modified: 2023-11-26 17:14 UTC (History)
0 users

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Attachments
Description and initial analysis (7.05 KB, text/plain)
2023-11-26 17:12 UTC, Marcus Hüwe 		Details
src code, tcpdump output, strace output (3.29 MB, application/x-tar)
2023-11-26 17:14 UTC, Marcus Hüwe 		Details
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Description Marcus Hüwe 2023-11-26 17:12:29 UTC 
Created attachment 870988 [details]
Description and initial analysis

We are facing a very strange behavior in a java.nio.channels.ServerSocketChannel
based single-threaded tcp server, when "lots" of client threads try to connect
to this server at the same time: It looks as if an ACKed tcp segment went
astray because its data does not seem to reach user space. Instead, the data
of the subsequent tcp segment arrives in user space.

The attached description.txt contains a detailed description + an initial analysis.
The attached repro.tar contains the java source code, the tcpdump output, and
the strace output.

Any ideas what's going on?:)
Comment 1 Marcus Hüwe 2023-11-26 17:14:06 UTC 
Created attachment 870989 [details]
src code, tcpdump output, strace output