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tipc: fix unsafe rcu locking when accessing publication list

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The binding table's 'cluster_scope' list is rcu protected to handle
races between threads changing the list and those traversing the list at
the same moment. We have now found that the function named_distribute()
uses the regular list_for_each() macro to traverse the said list.
Likewise, the function tipc_named_withdraw() is removing items from the
same list using the regular list_del() call. When these two functions
execute in parallel we see occasional crashes.

This commit fixes this by adding the missing _rcu() suffixes.

Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tung Nguyen 2018-10-12 22:46:55 +02:00 committed by David S. Miller
parent 7ec8dc96e1
commit d3092b2efc
1 changed files with 2 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
net/tipc/name_distr.c
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@ -115,7 +115,7 @@ struct sk_buff *tipc_named_withdraw(struct net *net, struct publication *publ)
struct sk_buff *buf;
struct distr_item *item;
list_del(&publ->binding_node);
list_del_rcu(&publ->binding_node);
if (publ->scope == TIPC_NODE_SCOPE)
return NULL;
@ -147,7 +147,7 @@ static void named_distribute(struct net *net, struct sk_buff_head *list,
ITEM_SIZE) * ITEM_SIZE;
u32 msg_rem = msg_dsz;
list_for_each_entry(publ, pls, binding_node) {
list_for_each_entry_rcu(publ, pls, binding_node) {
/* Prepare next buffer: */
if (!skb) {
skb = named_prepare_buf(net, PUBLICATION, msg_rem,