4.9-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Eremin dmitry.eremin@intel.com
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@intel.com Reviewed-by: Andreas Dilger andreas.dilger@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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)