On Wed, Oct 22, 2025 at 10:01 PM Jakub Kicinski <[email protected]> wrote: > > On Wed, 22 Oct 2025 10:39:56 -0700 Gustavo Luiz Duarte wrote: > > This series fixes a race condition in netconsole's userdata handling > > where concurrent message transmission could read partially updated > > userdata fields, resulting in corrupted netconsole output. > > > > The first patch adds a selftest that reproduces the race condition by > > continuously sending messages while rapidly changing userdata values, > > detecting any torn reads in the output. > > > > The second patch fixes the issue by ensuring update_userdata() holds > > the target_list_lock while updating both extradata_complete and > > userdata_length, preventing readers from seeing inconsistent state. > > > > This targets net tree as it fixes a bug introduced in commit df03f830d099 > > ("net: netconsole: cache userdata formatted string in netconsole_target"). > > This test is skipping on debug kernel builds in netdev CI. > > TAP version 13 > 1..1 > # overriding timeout to 360 > # selftests: drivers/net: netcons_race_userdata.sh > # socat died before we could check 10000 messages. Skipping test. > ok 1 selftests: drivers/net: netcons_race_userdata.sh # SKIP > > We can't have skips for SW tests. > > I think Breno was fighting with a similar problem in the past. > Not sure what he ended up doing. Maybe just leave it at the print? > Don't actually mark the test as skipped? > > Slightly more advanced option is to only do that if KSFT_MACHINE_SLOW > per: > https://github.com/linux-netdev/nipa/wiki/How-to-run-netdev-selftests-CI-style#dealing-with-slow-runners-in-performancelatency-tests
There are two reasons for hitting this skip. 1. The hardcoded 2s timeout in listen_port_and_save_to() expired 2. socat died or failed to start for mysterious reasons #1 should probably be a success (we ran the test for this long and no corruption found), and for #2 we can try to return whatever exit code socat give us. Retrieving socat return code is a bit tricky because we are running it in a subshell, but we can save it in a temp file. I can also send a follow up patch to use a longer timeout in listen_port_and_save_to() if KSFT_MACHINE_SLOW > -- > pw-bot: cr
