linux/tools/testing
Ido Schimmel f8fded7536 selftests: net: Fix flaky neighbor garbage collection test
The purpose of the "Periodic garbage collection" test case is to make
sure that "extern_valid" neighbors are not flushed during periodic
garbage collection, unlike regular neighbor entries.

The test case is currently doing the following:

1. Changing the base reachable time to 10 seconds so that periodic
   garbage collection will run every 5 seconds.

2. Changing the garbage collection stale time to 5 seconds so that
   neighbors that have not been used in the last 5 seconds will be
   considered for removal.

3. Waiting for the base reachable time change to take effect.

4. Adding an "extern_valid" neighbor, a non-"extern_valid" neighbor and
   a bunch of other neighbors so that the threshold ("thresh1") will be
   crossed and stale neighbors will be flushed during garbage
   collection.

5. Waiting for 10 seconds to give garbage collection a chance to run.

6. Checking that the "extern_valid" neighbor was not flushed and that
   the non-"extern_valid" neighbor was flushed.

The test sometimes fails in the netdev CI because the non-"extern_valid"
neighbor was not flushed. I am unable to reproduce this locally, but my
theory that since we do not know exactly when the periodic garbage
collection runs, it is possible for it to run at a time when the
non-"extern_valid" neighbor is still not considered stale.

Fix by moving the addition of the two neighbors before step 3 and by
reducing the garbage collection stale time to 1 second, to ensure that
both neighbors are considered stale when garbage collection runs.

Fixes: 171f2ee31a ("selftests: net: Add a selftest for externally validated neighbor entries")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/netdev/20250728093504.4ebbd73c@kernel.org/
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250731110914.506890-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-01 13:51:41 -07:00
..
crypto/chacha20-s390 crypto: lib/chacha - strongly type the ChaCha state 2025-05-12 13:32:53 +08:00
cxl cxl/test: Simplify fw_buf_checksum_show() 2025-07-04 10:18:52 -07:00
fault-injection
ktest
kunit Revert "kunit: configs: Enable CONFIG_INIT_STACK_ALL_PATTERN in all_tests" 2025-06-03 11:20:21 +02:00
memblock memblock: add MEMBLOCK_RSRV_KERN flag 2025-05-12 23:50:38 -07:00
nvdimm
radix-tree maple_tree: add sufficient height 2025-05-11 17:48:29 -07:00
rbtree
scatterlist
selftests selftests: net: Fix flaky neighbor garbage collection test 2025-08-01 13:51:41 -07:00
shared
vma fs: consistently use can_mmap_file() helper 2025-06-17 13:47:22 +02:00
vsock vsock/test: fix vsock_ioctl_int() check for unsupported ioctl 2025-07-16 16:14:00 -07:00