4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dmitry Eremin <dmitry.eremin@xxxxxxxxx>
commit 9b046013e5837f8a58453d1e9f8e01d03adb7fe7 upstream.
The logic of the original commit 4d99b2581eff ("staging: lustre: avoid
intensive reconnecting for ko2iblnd") was assumed conditional free of
struct kib_conn if the second argument free_conn in function
kiblnd_destroy_conn(struct kib_conn *conn, bool free_conn) is true.
But this hunk of code was dropped from original commit. As result the logic
works wrong and current code use struct kib_conn after free.
> drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
> 3317 kiblnd_destroy_conn(conn, !peer);
> ^^^^ Freed always (but should be conditionally)
> 3318
> 3319 spin_lock_irqsave(lock, flags);
> 3320 if (!peer)
> 3321 continue;
> 3322
> 3323 conn->ibc_peer = peer;
> ^^^^^^^^^^^^^^ Use after free
> 3324 if (peer->ibp_reconnected < KIB_RECONN_HIGH_RACE)
> 3325 list_add_tail(&conn->ibc_list,
> ^^^^^^^^^^^^^^ Use after free
> 3326 &kiblnd_data.kib_reconn_list);
> 3327 else
> 3328 list_add_tail(&conn->ibc_list,
> ^^^^^^^^^^^^^^ Use after free
> 3329 &kiblnd_data.kib_reconn_wait);
To avoid confusion this fix moved the freeing a struct kib_conn outside of
the function kiblnd_destroy_conn() and free as it was intended in original
commit.
Fixes: 4d99b2581eff ("staging: lustre: avoid intensive reconnecting for ko2iblnd")
Signed-off-by: Dmitry Eremin <Dmitry.Eremin@xxxxxxxxx>
Reviewed-by: Andreas Dilger <andreas.dilger@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c | 7 +++----
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h | 2 +-
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 6 ++++--
3 files changed, 8 insertions(+), 7 deletions(-)
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
@@ -824,14 +824,15 @@ struct kib_conn *kiblnd_create_conn(stru
return conn;
failed_2:
- kiblnd_destroy_conn(conn, true);
+ kiblnd_destroy_conn(conn);
+ LIBCFS_FREE(conn, sizeof(*conn));
failed_1:
LIBCFS_FREE(init_qp_attr, sizeof(*init_qp_attr));
failed_0:
return NULL;
}
-void kiblnd_destroy_conn(struct kib_conn *conn, bool free_conn)
+void kiblnd_destroy_conn(struct kib_conn *conn)
{
struct rdma_cm_id *cmid = conn->ibc_cmid;
struct kib_peer *peer = conn->ibc_peer;
@@ -894,8 +895,6 @@ void kiblnd_destroy_conn(struct kib_conn
rdma_destroy_id(cmid);
atomic_dec(&net->ibn_nconns);
}
-
- LIBCFS_FREE(conn, sizeof(*conn));
}
int kiblnd_close_peer_conns_locked(struct kib_peer *peer, int why)
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h
@@ -1018,7 +1018,7 @@ int kiblnd_close_peer_conns_locked(stru
struct kib_conn *kiblnd_create_conn(struct kib_peer *peer,
struct rdma_cm_id *cmid,
int state, int version);
-void kiblnd_destroy_conn(struct kib_conn *conn, bool free_conn);
+void kiblnd_destroy_conn(struct kib_conn *conn);
void kiblnd_close_conn(struct kib_conn *conn, int error);
void kiblnd_close_conn_locked(struct kib_conn *conn, int error);
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
@@ -3323,11 +3323,13 @@ kiblnd_connd(void *arg)
spin_unlock_irqrestore(lock, flags);
dropped_lock = 1;
- kiblnd_destroy_conn(conn, !peer);
+ kiblnd_destroy_conn(conn);
spin_lock_irqsave(lock, flags);
- if (!peer)
+ if (!peer) {
+ kfree(conn);
continue;
+ }
conn->ibc_peer = peer;
if (peer->ibp_reconnected < KIB_RECONN_HIGH_RACE)