From: Kuniyuki Iwashima Date: Fri, 22 Jul 2022 18:22:02 +0000 (-0700) Subject: tcp: Fix a data-race around sysctl_tcp_comp_sack_slack_ns. X-Git-Tag: v5.18.16~27 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2dc6e8f72d0d7f5d9e15a8940f7c3b9505e672ea;p=thirdparty%2Fkernel%2Fstable.git tcp: Fix a data-race around sysctl_tcp_comp_sack_slack_ns. [ Upstream commit 22396941a7f343d704738360f9ef0e6576489d43 ] While reading sysctl_tcp_comp_sack_slack_ns, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: a70437cc09a1 ("tcp: add hrtimer slack to sack compression") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 3591a25a86311..5de396075a27c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5551,7 +5551,7 @@ send_now: rtt * (NSEC_PER_USEC >> 3)/20); sock_hold(sk); hrtimer_start_range_ns(&tp->compressed_ack_timer, ns_to_ktime(delay), - sock_net(sk)->ipv4.sysctl_tcp_comp_sack_slack_ns, + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_comp_sack_slack_ns), HRTIMER_MODE_REL_PINNED_SOFT); }