net:so_txtime.sh in ubuntu_kernel_selftests failed with ./so_txtime: recv: timeout: Resource temporarily unavailable

[Po-Hsu Lin]

This is not a regression, but seems to be a flaky test (racing issue?)

This has been recorded for J-oracle but without a proper bug report. Found on F-gcp-5.15 this cycle.

Test failed with:
  ./so_txtime: recv: timeout: Resource temporarily unavailable

Test log:
Running 'make run_tests -C net TEST_PROGS=so_txtime.sh TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'
 make --no-builtin-rules ARCH=x86 -C ../../../.. headers_install
 make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
   INSTALL ./usr/include
 make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
 TAP version 13
 1..1
 # selftests: net: so_txtime.sh
 # ./so_txtime: recv: timeout: Resource temporarily unavailable
 #
 # SO_TXTIME ipv4 clock monotonic
 not ok 1 selftests: net: so_txtime.sh # exit=1