From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6004515AE3 for ; Wed, 9 Aug 2023 10:47:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5BBEC433C8; Wed, 9 Aug 2023 10:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691578063; bh=GrrhLshHlUq7TpMPhhcL1vaxnPxupLHT9ww0CF7Ahzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a3qzIiLtcWTKx1pT2xsYroDZpzDvuPgRucLZvlvlzVKz3JnHRwR9fIlVjx49Wi+l7 rGlN0e5m2AhTIyhh0btDUifzvyKcnfCwkQiPI1U3DO/23onOHxPTH/I+umI6X+S9Bk Xy0V4XYR3nTRcFM/6j+889aTsDxwIZvhiOvJWecM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , David Ahern , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.4 092/165] tcp_metrics: annotate data-races around tm->tcpm_vals[] Date: Wed, 9 Aug 2023 12:40:23 +0200 Message-ID: <20230809103645.805122026@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103642.720851262@linuxfoundation.org> References: <20230809103642.720851262@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit 8c4d04f6b443869d25e59822f7cec88d647028a9 ] tm->tcpm_vals[] values can be read or written locklessly. Add needed READ_ONCE()/WRITE_ONCE() to document this, and force use of tcp_metric_get() and tcp_metric_set() Fixes: 51c5d0c4b169 ("tcp: Maintain dynamic metrics in local cache.") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/tcp_metrics.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 131fa30049691..fd4ab7a51cef2 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -63,17 +63,19 @@ static bool tcp_metric_locked(struct tcp_metrics_block *tm, return READ_ONCE(tm->tcpm_lock) & (1 << idx); } -static u32 tcp_metric_get(struct tcp_metrics_block *tm, +static u32 tcp_metric_get(const struct tcp_metrics_block *tm, enum tcp_metric_index idx) { - return tm->tcpm_vals[idx]; + /* Paired with WRITE_ONCE() in tcp_metric_set() */ + return READ_ONCE(tm->tcpm_vals[idx]); } static void tcp_metric_set(struct tcp_metrics_block *tm, enum tcp_metric_index idx, u32 val) { - tm->tcpm_vals[idx] = val; + /* Paired with READ_ONCE() in tcp_metric_get() */ + WRITE_ONCE(tm->tcpm_vals[idx], val); } static bool addr_same(const struct inetpeer_addr *a, @@ -115,13 +117,16 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, WRITE_ONCE(tm->tcpm_lock, val); msval = dst_metric_raw(dst, RTAX_RTT); - tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; + tcp_metric_set(tm, TCP_METRIC_RTT, msval * USEC_PER_MSEC); msval = dst_metric_raw(dst, RTAX_RTTVAR); - tm->tcpm_vals[TCP_METRIC_RTTVAR] = msval * USEC_PER_MSEC; - tm->tcpm_vals[TCP_METRIC_SSTHRESH] = dst_metric_raw(dst, RTAX_SSTHRESH); - tm->tcpm_vals[TCP_METRIC_CWND] = dst_metric_raw(dst, RTAX_CWND); - tm->tcpm_vals[TCP_METRIC_REORDERING] = dst_metric_raw(dst, RTAX_REORDERING); + tcp_metric_set(tm, TCP_METRIC_RTTVAR, msval * USEC_PER_MSEC); + tcp_metric_set(tm, TCP_METRIC_SSTHRESH, + dst_metric_raw(dst, RTAX_SSTHRESH)); + tcp_metric_set(tm, TCP_METRIC_CWND, + dst_metric_raw(dst, RTAX_CWND)); + tcp_metric_set(tm, TCP_METRIC_REORDERING, + dst_metric_raw(dst, RTAX_REORDERING)); if (fastopen_clear) { tm->tcpm_fastopen.mss = 0; tm->tcpm_fastopen.syn_loss = 0; @@ -667,7 +672,7 @@ static int tcp_metrics_fill_info(struct sk_buff *msg, if (!nest) goto nla_put_failure; for (i = 0; i < TCP_METRIC_MAX_KERNEL + 1; i++) { - u32 val = tm->tcpm_vals[i]; + u32 val = tcp_metric_get(tm, i); if (!val) continue; -- 2.40.1