Any process is able to send netlink messages with leftover bytes.
Make the warning rate-limited to prevent too much log spam.

The warning is supposed to help find userspace bugs, so print the
triggering command name to implicate the buggy program.

[v2: Use pr_warn_ratelimited instead of printk_ratelimited.]

Signed-off-by: Michal Schmidt <redacted>
---
 lib/nlattr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/nlattr.c b/lib/nlattr.c
index fc67547..10ad042 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c

@@ -201,8 +201,8 @@ int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 	}
 
 	if (unlikely(rem > 0))
-		printk(KERN_WARNING "netlink: %d bytes leftover after parsing "
-		       "attributes.\n", rem);
+		pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n",
+				    rem, current->comm);
 
 	err = 0;
 errout:

-- 
1.9.3