[merged] net-fix-iteration-for-sctp-transport-seq_files.patch removed from -mm tree

[merged] net-fix-iteration-for-sctp-transport-seq_files.patch removed from -mm tree

[akpm]

The patch titled
     Subject: net: fix iteration for sctp transport seq_files
has been removed from the -mm tree.  Its filename was
     net-fix-iteration-for-sctp-transport-seq_files.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: NeilBrown <neilb@suse.de>
Subject: net: fix iteration for sctp transport seq_files

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.

Link: https://lkml.kernel.org/r/161248539022.21478.17038123892954492263.stgit@noble1
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Xin Long <lucien.xin@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 net/sctp/proc.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

--- a/net/sctp/proc.c~net-fix-iteration-for-sctp-transport-seq_files
+++ a/net/sctp/proc.c
@@ -215,6 +215,12 @@ static void sctp_transport_seq_stop(stru
 {
 	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);
 }
 
@@ -222,6 +228,12 @@ static void *sctp_transport_seq_next(str
 {
 	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);
@@ -277,8 +289,6 @@ static int sctp_assocs_seq_show(struct s
 		sk->sk_rcvbuf);
 	seq_printf(seq, "\n");
 
-	sctp_transport_put(transport);
-
 	return 0;
 }
 
@@ -354,8 +364,6 @@ static int sctp_remaddr_seq_show(struct
 		seq_printf(seq, "\n");
 	}
 
-	sctp_transport_put(transport);
-
 	return 0;
 }
 
_

Patches currently in -mm which might be from neilb@suse.de are

seq_file-document-how-per-entry-resources-are-managed.patch
x86-fix-seq_file-iteration-for-pat-memtypec.patch