lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Thu, 12 May 2022 18:33:21 +0800
From:   Liu Jian <liujian56@...wei.com>
To:     <edumazet@...gle.com>, <davem@...emloft.net>,
        <yoshfuji@...ux-ipv6.org>, <dsahern@...nel.org>, <kuba@...nel.org>,
        <pabeni@...hat.com>, <ncardwell@...gle.com>,
        <netdev@...r.kernel.org>
CC:     <liujian56@...wei.com>
Subject: [PATCH net] tcp: Add READ_ONCE() to read tcp_orphan_count

The tcp_orphan_count per-CPU variable is read locklessly, so this commit
add the READ_ONCE() to a load in order to avoid below KCSAN warnning:

BUG: KCSAN: data-race in tcp_orphan_count_sum net/ipv4/tcp.c:2476 [inline]
BUG: KCSAN: data-race in tcp_orphan_update+0x64/0x100 net/ipv4/tcp.c:2487

race at unknown origin, with read to 0xffff9c63bbdac7a8 of 4 bytes by interrupt on cpu 2:
 tcp_orphan_count_sum net/ipv4/tcp.c:2476 [inline]
 tcp_orphan_update+0x64/0x100 net/ipv4/tcp.c:2487
 call_timer_fn+0x33/0x210 kernel/time/timer.c:1414

Fixes: 19757cebf0c5 ("tcp: switch orphan_count to bare per-cpu counters")
Signed-off-by: Liu Jian <liujian56@...wei.com>
---
 net/ipv4/tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cf18fbcbf123..7245609f41e6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2718,7 +2718,7 @@ int tcp_orphan_count_sum(void)
 	int i, total = 0;
 
 	for_each_possible_cpu(i)
-		total += per_cpu(tcp_orphan_count, i);
+		total += READ_ONCE(per_cpu(tcp_orphan_count, i));
 
 	return max(total, 0);
 }
-- 
2.17.1

Powered by blists - more mailing lists