From: Dotan Barak <dotanb@dev.mellanox.co.il>
Date: Wed, 12 Jun 2013 13:20:36 +0000 (+0200)
Subject: IB/srp: Fix remove_one crash due to resource exhaustion
X-Git-Tag: upstream/snapshot3+hdmi~4705^2~1^7~6
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1fe0cb848890a3f4dd965fdce8b4108feb03971f;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

IB/srp: Fix remove_one crash due to resource exhaustion

If the add_one callback fails during driver load no resources are
allocated so there isn't a need to release any resources. Trying
to clean the resource may lead to the following kernel panic:

    BUG: unable to handle kernel NULL pointer dereference at (null)
    IP: [<ffffffffa0132331>] srp_remove_one+0x31/0x240 [ib_srp]
    RIP: 0010:[<ffffffffa0132331>]  [<ffffffffa0132331>] srp_remove_one+0x31/0x240 [ib_srp]
    Process rmmod (pid: 4562, threadinfo ffff8800dd738000, task ffff8801167e60c0)
    Call Trace:
     [<ffffffffa024500e>] ib_unregister_client+0x4e/0x120 [ib_core]
     [<ffffffffa01361bd>] srp_cleanup_module+0x15/0x71 [ib_srp]
     [<ffffffff810ac6a4>] sys_delete_module+0x194/0x260
     [<ffffffff8100b0f2>] system_call_fastpath+0x16/0x1b

Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Reviewed-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
---

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 7ccf328..368d160 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -2507,6 +2507,8 @@ static void srp_remove_one(struct ib_device *device)
 	struct srp_target_port *target;
 
 	srp_dev = ib_get_client_data(device, &srp_client);
+	if (!srp_dev)
+		return;
 
 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
 		device_unregister(&host->dev);