The patch titled
Subject: net: fix iteration for sctp transport seq_files
has been added to the -mm tree. Its filename is
net-fix-iteration-for-sctp-transport-seq_files.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/net-fix-iteration-for-sctp-transport-seq_files.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/net-fix-iteration-for-sctp-transport-seq_files.patch
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------------------------------------------------------
From: NeilBrown <neilb@xxxxxxx>
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@xxxxxxx>
Reported-by: Xin Long <lucien.xin@xxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Vlad Yasevich <vyasevich@xxxxxxxxx>
Cc: Neil Horman <nhorman@xxxxxxxxxxxxx>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxx are
seq_file-document-how-per-entry-resources-are-managed.patch
x86-fix-seq_file-iteration-for-pat-memtypec.patch
net-fix-iteration-for-sctp-transport-seq_files.patch
