This is a note to let you know that I've just added the patch titled
selftests: pmtu.sh: Kill tcpdump processes launched by subshell.
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-pmtu.sh-kill-tcpdump-processes-launched-by.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f667d63d04b7ba0aa2a5590481f2d0e195e4bf3c
Author: Guillaume Nault <gnault@xxxxxxxxxx>
Date: Tue Mar 8 23:15:00 2022 +0100
selftests: pmtu.sh: Kill tcpdump processes launched by subshell.
[ Upstream commit 18dfc667550fe9c032a6dcc3402b50e691e18029 ]
The cleanup() function takes care of killing processes launched by the
test functions. It relies on variables like ${tcpdump_pids} to get the
relevant PIDs. But tests are run in their own subshell, so updated
*_pids values are invisible to other shells. Therefore cleanup() never
sees any process to kill:
$ ./tools/testing/selftests/net/pmtu.sh -t pmtu_ipv4_exception
TEST: ipv4: PMTU exceptions [ OK ]
TEST: ipv4: PMTU exceptions - nexthop objects [ OK ]
$ pgrep -af tcpdump
6084 tcpdump -s 0 -i veth_A-R1 -w pmtu_ipv4_exception_veth_A-R1.pcap
6085 tcpdump -s 0 -i veth_R1-A -w pmtu_ipv4_exception_veth_R1-A.pcap
6086 tcpdump -s 0 -i veth_R1-B -w pmtu_ipv4_exception_veth_R1-B.pcap
6087 tcpdump -s 0 -i veth_B-R1 -w pmtu_ipv4_exception_veth_B-R1.pcap
6088 tcpdump -s 0 -i veth_A-R2 -w pmtu_ipv4_exception_veth_A-R2.pcap
6089 tcpdump -s 0 -i veth_R2-A -w pmtu_ipv4_exception_veth_R2-A.pcap
6090 tcpdump -s 0 -i veth_R2-B -w pmtu_ipv4_exception_veth_R2-B.pcap
6091 tcpdump -s 0 -i veth_B-R2 -w pmtu_ipv4_exception_veth_B-R2.pcap
6228 tcpdump -s 0 -i veth_A-R1 -w pmtu_ipv4_exception_veth_A-R1.pcap
6229 tcpdump -s 0 -i veth_R1-A -w pmtu_ipv4_exception_veth_R1-A.pcap
6230 tcpdump -s 0 -i veth_R1-B -w pmtu_ipv4_exception_veth_R1-B.pcap
6231 tcpdump -s 0 -i veth_B-R1 -w pmtu_ipv4_exception_veth_B-R1.pcap
6232 tcpdump -s 0 -i veth_A-R2 -w pmtu_ipv4_exception_veth_A-R2.pcap
6233 tcpdump -s 0 -i veth_R2-A -w pmtu_ipv4_exception_veth_R2-A.pcap
6234 tcpdump -s 0 -i veth_R2-B -w pmtu_ipv4_exception_veth_R2-B.pcap
6235 tcpdump -s 0 -i veth_B-R2 -w pmtu_ipv4_exception_veth_B-R2.pcap
Fix this by running cleanup() in the context of the test subshell.
Now that each test cleans the environment after completion, there's no
need for calling cleanup() again when the next test starts. So let's
drop it from the setup() function. This is okay because cleanup() is
also called when pmtu.sh starts, so even the first test starts in a
clean environment.
Also, use tcpdump's immediate mode. Otherwise it might not have time to
process buffered packets, resulting in missing packets or even empty
pcap files for short tests.
Note: PAUSE_ON_FAIL is still evaluated before cleanup(), so one can
still inspect the test environment upon failure when using -p.
Fixes: a92a0a7b8e7c ("selftests: pmtu: Simplify cleanup and namespace names")
Signed-off-by: Guillaume Nault <gnault@xxxxxxxxxx>
Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/net/pmtu.sh b/tools/testing/selftests/net/pmtu.sh
index 3429767cadcd..88be9083b923 100755
--- a/tools/testing/selftests/net/pmtu.sh
+++ b/tools/testing/selftests/net/pmtu.sh
@@ -579,7 +579,6 @@ setup_routing() {
setup() {
[ "$(id -u)" -ne 0 ] && echo " need to run as root" && return $ksft_skip
- cleanup
for arg do
eval setup_${arg} || { echo " ${arg} not supported"; return 1; }
done
@@ -590,7 +589,7 @@ trace() {
for arg do
[ "${ns_cmd}" = "" ] && ns_cmd="${arg}" && continue
- ${ns_cmd} tcpdump -s 0 -i "${arg}" -w "${name}_${arg}.pcap" 2> /dev/null &
+ ${ns_cmd} tcpdump --immediate-mode -s 0 -i "${arg}" -w "${name}_${arg}.pcap" 2> /dev/null &
tcpdump_pids="${tcpdump_pids} $!"
ns_cmd=
done
@@ -1182,6 +1181,10 @@ run_test() {
unset IFS
+ # Since cleanup() relies on variables modified by this subshell, it
+ # has to run in this context.
+ trap cleanup EXIT
+
if [ "$VERBOSE" = "1" ]; then
printf "\n##########################################################################\n\n"
fi
