From: NeilBrown neilb@suse.de
stable inclusion from linux-4.19.177 commit 7436ceb2b78f334e292d72bb3d2ca4d5deb367df
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commit af8085f3a4712c57d0dd415ad543bac85780375c upstream.
The sctp transport seq_file iterators take a reference to the transport in the ->start and ->next functions and releases the reference in the ->show function. The preferred handling for such resources is to release them in the subsequent ->next or ->stop function call.
Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") there is no guarantee that ->show will be called after ->next, so this function can now leak references.
So move the sctp_transport_put() call to ->next and ->stop.
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface") Reported-by: Xin Long lucien.xin@gmail.com Signed-off-by: NeilBrown neilb@suse.de Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com
Signed-off-by: Aichun Li liaichun@huawei.com reviewed-by: wangxiaopeng wangxiaopeng7@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- net/sctp/proc.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/sctp/proc.c b/net/sctp/proc.c index a644292f9faf..84f79ac4b984 100644 --- a/net/sctp/proc.c +++ b/net/sctp/proc.c @@ -230,6 +230,12 @@ static void sctp_transport_seq_stop(struct seq_file *seq, void *v) { struct sctp_ht_iter *iter = seq->private;
+ if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + sctp_transport_walk_stop(&iter->hti); }
@@ -237,6 +243,12 @@ static void *sctp_transport_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct sctp_ht_iter *iter = seq->private;
+ if (v && v != SEQ_START_TOKEN) { + struct sctp_transport *transport = v; + + sctp_transport_put(transport); + } + ++*pos;
return sctp_transport_get_next(seq_file_net(seq), &iter->hti); @@ -292,8 +304,6 @@ static int sctp_assocs_seq_show(struct seq_file *seq, void *v) sk->sk_rcvbuf); seq_printf(seq, "\n");
- sctp_transport_put(transport); - return 0; }
@@ -369,8 +379,6 @@ static int sctp_remaddr_seq_show(struct seq_file *seq, void *v) seq_printf(seq, "\n"); }
- sctp_transport_put(transport); - return 0; }