This is a note to let you know that I've just added the patch titled

staging: lustre: separate a connection destroy from free struct

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the staging-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From 9b046013e5837f8a58453d1e9f8e01d03adb7fe7 Mon Sep 17 00:00:00 2001

From: Dmitry Eremin dmitry.eremin@intel.com Date: Thu, 25 Jan 2018 16:51:04 +0300 Subject: 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: stable@vger.kernel.org # v4.6 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 --- 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)