[PATCH 4.6 089/100] IB/srp: Fix srp_create_target() error handling

Greg Kroah-Hartman
2016-05-30T20:50:24Z

From: Bart Van Assche <bart.vanassche@sandisk.com>

commit f83b2561a6d4ff12959660ad597580097b744941 upstream.

Avoid that the following kernel oops occurs if memory pool
allocation fails:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa048d0a0>] ib_drain_rq+0x0/0x20 [ib_core]
Call Trace:
[<ffffffffa04af386>] srp_create_target+0xca6/0x13a9 [ib_srp]
[<ffffffff813cc863>] dev_attr_store+0x13/0x20
[<ffffffff81214b50>] sysfs_kf_write+0x40/0x50
[<ffffffff81213f1c>] kernfs_fop_write+0x13c/0x180
[<ffffffff81197683>] __vfs_write+0x23/0xf0
[<ffffffff81198744>] vfs_write+0xa4/0x1a0
[<ffffffff81199a44>] SyS_write+0x44/0xa0
[<ffffffff8159e3e9>] entry_SYSCALL_64_fastpath+0x1c/0xac

Fixes: 1dc7b1f10dcb ("IB/srp: use the new CQ API")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/ulp/srp/ib_srp.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -448,16 +448,16 @@ static struct srp_fr_pool *srp_alloc_fr_

/**
* srp_destroy_qp() - destroy an RDMA queue pair
- * @ch: SRP RDMA channel.
+ * @qp: RDMA queue pair.
*
* Drain the qp before destroying it. This avoids that the receive
* completion handler can access the queue pair while it is
* being destroyed.
*/
-static void srp_destroy_qp(struct srp_rdma_ch *ch)
+static void srp_destroy_qp(struct ib_qp *qp)
{
- ib_drain_rq(ch->qp);
- ib_destroy_qp(ch->qp);
+ ib_drain_rq(qp);
+ ib_destroy_qp(qp);
}

static int srp_create_ch_ib(struct srp_rdma_ch *ch)
@@ -530,7 +530,7 @@ static int srp_create_ch_ib(struct srp_r
}

if (ch->qp)
- srp_destroy_qp(ch);
+ srp_destroy_qp(ch->qp);
if (ch->recv_cq)
ib_free_cq(ch->recv_cq);
if (ch->send_cq)
@@ -554,7 +554,7 @@ static int srp_create_ch_ib(struct srp_r
return 0;

err_qp:
- srp_destroy_qp(ch);
+ srp_destroy_qp(qp);

err_send_cq:
ib_free_cq(send_cq);
@@ -597,7 +597,7 @@ static void srp_free_ch_ib(struct srp_ta
ib_destroy_fmr_pool(ch->fmr_pool);
}

- srp_destroy_qp(ch);
+ srp_destroy_qp(ch->qp);
ib_free_cq(ch->send_cq);
ib_free_cq(ch->recv_cq);