media: vb2: be sure to unlock mutex on errors

BugLink: https://bugs.launchpad.net/bugs/1837477
commit c06ef2e9acef4cda1feee2ce055b8086e33d251a upstream.

As reported by smatch:
drivers/media/common/videobuf2/videobuf2-core.c: drivers/media/common/videobuf2/videobuf2-core.c:2159 vb2_mmap() warn: inconsistent returns 'mutex:&q->mmap_lock'.
  Locked on:   line 2148
  Unlocked on: line 2100
               line 2108
               line 2113
               line 2118
               line 2156
               line 2159

There is one error condition that doesn't unlock a mutex.

Fixes: cd26d1c4d1bc ("media: vb2: vb2_mmap: move lock up")
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 5a7c18c1cdd23551352a73db747184093b3364f9..1d12cf1e9912fbec334472a2c2c90853f6e95844 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1953,7 +1953,8 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
        if (length < (vma->vm_end - vma->vm_start)) {
                dprintk(1,
                        "MMAP invalid, as it would overflow buffer length\n");
-               return -EINVAL;
+               ret = -EINVAL;
+               goto unlock;
        }
 
        ret = call_memop(vb, mmap, vb->planes[plane].mem_priv, vma);