selftests/net: toeplitz: fix race on tpacket_v3 block close
authorWillem de Bruijn <willemb@google.com>
Wed, 18 Jan 2023 15:18:47 +0000 (10:18 -0500)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 1 Feb 2023 07:27:14 +0000 (08:27 +0100)
commit18346db1854ab3cf1c52ec6b7f9bcf8f63db096b
tree3474090275ec6a8e66b9a9816adeaeee798decd5
parentcaa28c7c83e362f83689356078826627819da220
selftests/net: toeplitz: fix race on tpacket_v3 block close

[ Upstream commit 903848249a781d76d59561d51676c95b3a4d7162 ]

Avoid race between process wakeup and tpacket_v3 block timeout.

The test waits for cfg_timeout_msec for packets to arrive. Packets
arrive in tpacket_v3 rings, which pass packets ("frames") to the
process in batches ("blocks"). The sk waits for req3.tp_retire_blk_tov
msec to release a block.

Set the block timeout lower than the process waiting time, else
the process may find that no block has been released by the time it
scans the socket list. Convert to a ring of more than one, smaller,
blocks with shorter timeouts. Blocks must be page aligned, so >= 64KB.

Fixes: 5ebfb4cc3048 ("selftests/net: toeplitz test")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230118151847.4124260-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tools/testing/selftests/net/toeplitz.c