gcc-4.9 warns that it cannot trace the state of the 'last_ackt' variable since the change to the TCP timestamping code, when CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
net/ipv4/tcp_input.c: In function 'tcp_clean_rtx_queue': include/net/tcp.h:757:23: error: 'last_ackt' may be used uninitialized in this function [-Werror=maybe-uninitialized] Other gcc versions, both older and newer do now show this warning. Removing the 'likely' annotation makes it go away, and has no effect on the object code without CONFIG_PROFILE_ANNOTATED_BRANCHES, as tested with gcc-4.9 and gcc-7.1.1, so this seems to be a safe workaround. Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock") Signed-off-by: Arnd Bergmann <a...@arndb.de> --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c5d7656beeee..c52bc8e35d4d 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3173,7 +3173,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) flag |= FLAG_SACK_RENEGING; - if (likely(first_ackt) && !(flag & FLAG_RETRANS_DATA_ACKED)) { + if (first_ackt && !(flag & FLAG_RETRANS_DATA_ACKED)) { seq_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, first_ackt); ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, last_ackt); } -- 2.9.0