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authorXin Long <lucien.xin@gmail.com>2017-06-10 09:48:14 +0300
committerDavid S. Miller <davem@davemloft.net>2017-06-10 23:18:10 +0300
commit581409dacc9176b0de1f6c4ca8d66e13aa8e1b29 (patch)
tree7364921671ba8789fec957642ed0835bf8953dfd /net
parentbf292f1b2c813f1d6ac49b04bd1a9863d8314266 (diff)
downloadlinux-581409dacc9176b0de1f6c4ca8d66e13aa8e1b29.tar.xz
sctp: disable BH in sctp_for_each_endpoint
Now sctp holds read_lock when foreach sctp_ep_hashtable without disabling BH. If CPU schedules to another thread A at this moment, the thread A may be trying to hold the write_lock with disabling BH. As BH is disabled and CPU cannot schedule back to the thread holding the read_lock, while the thread A keeps waiting for the read_lock. A dead lock would be triggered by this. This patch is to fix this dead lock by calling read_lock_bh instead to disable BH when holding the read_lock in sctp_for_each_endpoint. Fixes: 626d16f50f39 ("sctp: export some apis or variables for sctp_diag and reuse some for proc") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/socket.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index f16c8d97b7f3..30aa0a529215 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4622,13 +4622,13 @@ int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *),
for (head = sctp_ep_hashtable; hash < sctp_ep_hashsize;
hash++, head++) {
- read_lock(&head->lock);
+ read_lock_bh(&head->lock);
sctp_for_each_hentry(epb, &head->chain) {
err = cb(sctp_ep(epb), p);
if (err)
break;
}
- read_unlock(&head->lock);
+ read_unlock_bh(&head->lock);
}
return err;