From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 9 Jan 2018 20:03:46 +0000 (+0300)
Subject: IB/hfi1: Prevent a NULL dereference
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b3049d3d0688b1647cba4a129b156a510dbbb0b4;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

IB/hfi1: Prevent a NULL dereference

commit 57194fa763bfa1a0908f30d4c77835beaa118fcb upstream.

In the original code, we set "fd->uctxt" to NULL and then dereference it
which will cause an Oops.

Fixes: f2a3bc00a03c ("IB/hfi1: Protect context array set/clear with spinlock")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index d9a1e9893136..fd28f09b4445 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -881,11 +881,11 @@ static int complete_subctxt(struct hfi1_filedata *fd)
 	}
 
 	if (ret) {
-		hfi1_rcd_put(fd->uctxt);
-		fd->uctxt = NULL;
 		spin_lock_irqsave(&fd->dd->uctxt_lock, flags);
 		__clear_bit(fd->subctxt, fd->uctxt->in_use_ctxts);
 		spin_unlock_irqrestore(&fd->dd->uctxt_lock, flags);
+		hfi1_rcd_put(fd->uctxt);
+		fd->uctxt = NULL;
 	}
 
 	return ret;