diff options
| author | Alexander Aring <aahringo@redhat.com> | 2026-04-27 18:59:34 +0300 |
|---|---|---|
| committer | David Teigland <teigland@redhat.com> | 2026-05-08 16:38:03 +0300 |
| commit | d2248cb70c070f8f04762872772e155b59016f17 (patch) | |
| tree | f1054e1f1bdd46f281cbaae330fe1a7cec199792 | |
| parent | b5314f2c6654a3616fd72777deb1ca766cc50618 (diff) | |
| download | linux-d2248cb70c070f8f04762872772e155b59016f17.tar.xz | |
dlm: fix add msg handle in send_queue ordered
In a benchmark scenario triggering a lot of requests that triggers a lot
of DLM messages on the network it can be that the mh->seq is not ordered
according the oldest seq number. This ordering is required by
dlm_receive_ack as "before(mh->seq, seq)" will stop to check for older
sequence numbers that are ordered in the tail of "node->send_queue".
The side effects of not having it correct ordered regarding
"before(mh->seq, seq)" are refcounting issues and use-after free.
I only was able to reproduce this issue in a experimental DLM branch
and a user space DLM benchmark that uses io_uring. After changing this I
don't experienced any refcounting with the sending buffer issues anymore.
Fixes: 489d8e559c659 ("fs: dlm: add reliable connection if reconnect")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
| -rw-r--r-- | fs/dlm/midcomms.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c index a5b363b4785f..6b522d4e2b7e 100644 --- a/fs/dlm/midcomms.c +++ b/fs/dlm/midcomms.c @@ -969,10 +969,10 @@ static void midcomms_new_msg_cb(void *data) atomic_inc(&mh->node->send_queue_cnt); spin_lock_bh(&mh->node->send_queue_lock); + /* need to be locked with list_add_tail_rcu() because list is ordered */ + mh->seq = atomic_fetch_inc(&mh->node->seq_send); list_add_tail_rcu(&mh->list, &mh->node->send_queue); spin_unlock_bh(&mh->node->send_queue_lock); - - mh->seq = atomic_fetch_inc(&mh->node->seq_send); } static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid, |