[PATCH 4.2.y-ckt 170/206] taskstats: fix nl parsing in accounting/getdelays.c

[Kamal Mostafa]

4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Nicolas Dichtel <nicolas.dichtel at 6wind.com>

commit 570d8e9398011a63590c281a36cdce311196608e upstream.

The type TASKSTATS_TYPE_NULL should always be ignored.

When jumping to the next attribute, only the length of the current
attribute should be added, not the length of all nested attributes.
This last bug was not visible before commit 80df554275c2, because the
kernel didn't put more than two nested attributes.

Fixes: a3baf649ca9c ("[PATCH] per-task-delay-accounting: documentation")
Fixes: 80df554275c2 ("taskstats: use the libnl API to align nlattr on 64-bit")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel at 6wind.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 Documentation/accounting/getdelays.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index f405780..9497d20 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -504,6 +504,8 @@ int main(int argc, char *argv[])
 						if (!loop)
 							goto done;
 						break;
+					case TASKSTATS_TYPE_NULL:
+						break;
 					default:
 						fprintf(stderr, "Unknown nested"
 							" nla_type %d\n",
@@ -511,7 +513,8 @@ int main(int argc, char *argv[])
 						break;
 					}
 					len2 += NLA_ALIGN(na->nla_len);
-					na = (struct nlattr *) ((char *) na + len2);
+					na = (struct nlattr *)((char *)na +
+							       NLA_ALIGN(na->nla_len));
 				}
 				break;
 
-- 
2.7.4