tools/accounting/getdelays.c: fix netlink attribute length

commit 4054ab64e29bb05b3dfe758fff3c38a74ba753bb upstream.

A recent change to the netlink code: 6e237d099fac ("netlink: Relax attr
validation for fixed length types") logs a warning when programs send
messages with invalid attributes (e.g., wrong length for a u32).  Yafang
reported this error message for tools/accounting/getdelays.c.

send_cmd() is wrongly adding 1 to the attribute length.  As noted in
include/uapi/linux/netlink.h nla_len should be NLA_HDRLEN + payload
length, so drop the +1.

Fixes: 9e06d3f9f6b1 ("per task delay accounting taskstats interface: documentation fix")
Reported-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200327173111.63922-1-dsahern@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/accounting/getdelays.c b/tools/accounting/getdelays.c
index 8cb504d..5ef1c15 100644 (file)
--- a/tools/accounting/getdelays.c
+++ b/tools/accounting/getdelays.c
@@ -136,7 +136,7 @@ static int send_cmd(int sd, __u16 nlmsg_type, __u32 nlmsg_pid,
        msg.g.version = 0x1;
        na = (struct nlattr *) GENLMSG_DATA(&msg);
        na->nla_type = nla_type;
-       na->nla_len = nla_len + 1 + NLA_HDRLEN;
+       na->nla_len = nla_len + NLA_HDRLEN;
        memcpy(NLA_DATA(na), nla_data, nla_len);
        msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);