This is a note to let you know that I've just added the patch titled
rds: tcp: atomically purge entries from rds_tcp_conn_list during netns delete
to the 4.15-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:
rds-tcp-atomically-purge-entries-from-rds_tcp_conn_list-during-netns-delete.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f10b4cff98c6977668434fbf5dd58695eeca2897 Mon Sep 17 00:00:00 2001
From: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
Date: Thu, 30 Nov 2017 11:11:29 -0800
Subject: rds: tcp: atomically purge entries from rds_tcp_conn_list during netns delete
From: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
commit f10b4cff98c6977668434fbf5dd58695eeca2897 upstream.
The rds_tcp_kill_sock() function parses the rds_tcp_conn_list
to find the rds_connection entries marked for deletion as part
of the netns deletion under the protection of the rds_tcp_conn_lock.
Since the rds_tcp_conn_list tracks rds_tcp_connections (which
have a 1:1 mapping with rds_conn_path), multiple tc entries in
the rds_tcp_conn_list will map to a single rds_connection, and will
be deleted as part of the rds_conn_destroy() operation that is
done outside the rds_tcp_conn_lock.
The rds_tcp_conn_list traversal done under the protection of
rds_tcp_conn_lock should not leave any doomed tc entries in
the list after the rds_tcp_conn_lock is released, else another
concurrently executiong netns delete (for a differnt netns) thread
may trip on these entries.
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/rds/tcp.c | 9 +++++++--
net/rds/tcp.h | 1 +
2 files changed, 8 insertions(+), 2 deletions(-)
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -307,7 +307,8 @@ static void rds_tcp_conn_free(void *arg)
rdsdebug("freeing tc %p\n", tc);
spin_lock_irqsave(&rds_tcp_conn_lock, flags);
- list_del(&tc->t_tcp_node);
+ if (!tc->t_tcp_node_detached)
+ list_del(&tc->t_tcp_node);
spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
kmem_cache_free(rds_tcp_conn_slab, tc);
@@ -532,8 +533,12 @@ static void rds_tcp_kill_sock(struct net
if (net != c_net || !tc->t_sock)
continue;
- if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
+ if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
list_move_tail(&tc->t_tcp_node, &tmp_list);
+ } else {
+ list_del(&tc->t_tcp_node);
+ tc->t_tcp_node_detached = true;
+ }
}
spin_unlock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
--- a/net/rds/tcp.h
+++ b/net/rds/tcp.h
@@ -12,6 +12,7 @@ struct rds_tcp_incoming {
struct rds_tcp_connection {
struct list_head t_tcp_node;
+ bool t_tcp_node_detached;
struct rds_conn_path *t_cpath;
/* t_conn_path_lock synchronizes the connection establishment between
* rds_tcp_accept_one and rds_tcp_conn_path_connect
Patches currently in stable-queue which might be from sowmini.varadhan@xxxxxxxxxx are
queue-4.15/rds-tcp-atomically-purge-entries-from-rds_tcp_conn_list-during-netns-delete.patch
queue-4.15/rds-tcp-correctly-sequence-cleanup-on-netns-deletion.patch