From 9b046013e5837f8a58453d1e9f8e01d03adb7fe7 Mon Sep 17 00:00:00 2001 From: Dmitry Eremin Date: Thu, 25 Jan 2018 16:51:04 +0300 Subject: [PATCH] staging: lustre: separate a connection destroy from free struct kib_conn 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. Cc: # v4.6 Fixes: 4d99b2581eff ("staging: lustre: avoid intensive reconnecting for ko2iblnd") Signed-off-by: Dmitry Eremin Reviewed-by: Andreas Dilger Signed-off-by: Greg Kroah-Hartman --- 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(-) diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c index 2ebc484385b3..ec84edfda271 100644 --- 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(struct kib_peer *peer, struct rdma_cm_id *cm return conn; failed_2: - kiblnd_destroy_conn(conn, true); + kiblnd_destroy_conn(conn); + kfree(conn); failed_1: kfree(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; @@ -889,8 +890,6 @@ void kiblnd_destroy_conn(struct kib_conn *conn, bool free_conn) rdma_destroy_id(cmid); atomic_dec(&net->ibn_nconns); } - - kfree(conn); } int kiblnd_close_peer_conns_locked(struct kib_peer *peer, int why) diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h index 171eced213f8..b18911d09e9a 100644 --- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h +++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.h @@ -1016,7 +1016,7 @@ int kiblnd_close_peer_conns_locked(struct kib_peer *peer, int why); 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); diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c index 9b3328c5d1e7..b3e7f28eb978 100644 --- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c +++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c @@ -3314,11 +3314,13 @@ 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)