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nft_tproxy_udp.sh flaky after Fedora 44 upgrade

TEST Jakub Kicinski 2 participants 3 messages Apr 8 – Apr 9

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Jakub Kicinski

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#0 lore raw

Hi Florian!

When you have a sec -- we upgraded the NIPA systems to Fedora 44 over the weekend, and nft_tproxy_udp.sh has gotten quite flaky:
https://netdev.bots.linux.dev/contest.html?test=nft-tproxy-udp-sh

One thing that we hit immediately is this, in case tproxy test uses socat:

commit e65d8b6f3092398efd7c74e722cb7a516d9a0d6d
Date: Sat Apr 4 16:01:03 2026 -0700

selftests: drv-net: adjust to socat changes

socat v1.8.1.0 now defaults to shut-null, it sends an extra 0-length UDP packet when sender disconnects. This breaks our tests which expect the exact packet sequence.

Add shut-none which was the old default where necessary.

#1 lore raw
Quoted 10 lines · Jakub Kicinski

When you have a sec -- we upgraded the NIPA systems to Fedora 44 over the weekend, and nft_tproxy_udp.sh has gotten quite flaky:
https://netdev.bots.linux.dev/contest.html?test=nft-tproxy-udp-sh

One thing that we hit immediately is this, in case tproxy test uses socat:

commit e65d8b6f3092398efd7c74e722cb7a516d9a0d6d
Date: Sat Apr 4 16:01:03 2026 -0700

Quoted 7 lines

selftests: drv-net: adjust to socat changes

socat v1.8.1.0 now defaults to shut-null, it sends an extra 0-length UDP packet when sender disconnects. This breaks our tests which expect the exact packet sequence.

Add shut-none which was the old default where necessary.

Thanks for the pointer, I will try to get to this later today.

#2 lore raw
Quoted 13 lines · Florian Westphal
Quoted 12 lines · Jakub Kicinski

When you have a sec -- we upgraded the NIPA systems to Fedora 44 over the weekend, and nft_tproxy_udp.sh has gotten quite flaky:
https://netdev.bots.linux.dev/contest.html?test=nft-tproxy-udp-sh

One thing that we hit immediately is this, in case tproxy test uses socat:

commit e65d8b6f3092398efd7c74e722cb7a516d9a0d6d
Date: Sat Apr 4 16:01:03 2026 -0700

selftests: drv-net: adjust to socat changes

Quoted 7 lines
Quoted 5 lines

socat v1.8.1.0 now defaults to shut-null, it sends an extra 0-length UDP packet when sender disconnects. This breaks our tests which expect the exact packet sequence.

Add shut-none which was the old default where necessary.

Thanks for the pointer, I will try to get to this later today.

No luck so far:

# grep PASS /tmp/log |wc -l
900
# grep -v PASS /tmp/log
# cat /etc/fedora-release
Fedora release 44 (Forty Four)

This on
commit d444044483a98264722ff77ffef407df0589c6c7 (HEAD, nipa/net-next-2026-04-09--06-00) with a debug build.
(non debug did not trigger anything either).