kernel: Revert "tcp: do not lock listener to process SYN packets"

This commit belongs to the patch set (https://lwn.net/Articles/659199/)
that attempts to remove the use of locks on the socket table by
relocating the SYN table to a separate hash table and adding a spin lock
to protect the SYN request queue. Adding only this commit introduces a
race condition for LineageOS kernels for TCP listens, since the TCP SYN
data structures can be corrupted.

A TCP curl bomb on a TCP listen port will corrupt the SYN accept backlog:

for i in $(seq 1 400); do curl -x localhost:443 https://myhost.com -L  --connect-timeout 30 -o /dev/null -sS & done

Run `ss -nltp` and usually the RecVQ column does not drain to 0.

This reverts commit 7d9f104f9cabe1d72a50c4816a48f64fc1da7a64.

This really needs to be reverted across all LineageOS forks:
https://gitlab.com/LineageOS/issues/android/-/issues/3916#note_669493796

Change-Id: Ia7969aeedae411677b307a8e094f9a4cc02b801d

0 files changed, 0 insertions, 0 deletions