From: Eric Dumazet edumazet@google.com
[ Upstream commit 0a9e5794b21e2d1303759ff8fe5f9215db7757ba ]
KCSAN reported multiple cpus can update use_time at the same time.
Adds READ_ONCE()/WRITE_ONCE() annotations.
Note that 32bit arches are not fully protected, but they will probably no longer be supported/used in 2106.
BUG: KCSAN: data-race in __xfrm_policy_check / __xfrm_policy_check
write to 0xffff88813e7ec108 of 8 bytes by interrupt on cpu 0: __xfrm_policy_check+0x6ae/0x17f0 net/xfrm/xfrm_policy.c:3664 __xfrm_policy_check2 include/net/xfrm.h:1174 [inline] xfrm_policy_check include/net/xfrm.h:1179 [inline] xfrm6_policy_check+0x2e9/0x320 include/net/xfrm.h:1189 udpv6_queue_rcv_one_skb+0x48/0xa30 net/ipv6/udp.c:703 udpv6_queue_rcv_skb+0x2d6/0x310 net/ipv6/udp.c:792 udp6_unicast_rcv_skb+0x16b/0x190 net/ipv6/udp.c:935 __udp6_lib_rcv+0x84b/0x9b0 net/ipv6/udp.c:1020 udpv6_rcv+0x4b/0x50 net/ipv6/udp.c:1133 ip6_protocol_deliver_rcu+0x99e/0x1020 net/ipv6/ip6_input.c:439 ip6_input_finish net/ipv6/ip6_input.c:484 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ip6_input+0xca/0x180 net/ipv6/ip6_input.c:493 dst_input include/net/dst.h:454 [inline] ip6_rcv_finish+0x1e9/0x2d0 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:302 [inline] ipv6_rcv+0x85/0x140 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core net/core/dev.c:5482 [inline] __netif_receive_skb+0x8b/0x1b0 net/core/dev.c:5596 process_backlog+0x23f/0x3b0 net/core/dev.c:5924 __napi_poll+0x65/0x390 net/core/dev.c:6485 napi_poll net/core/dev.c:6552 [inline] net_rx_action+0x37e/0x730 net/core/dev.c:6663 __do_softirq+0xf2/0x2c7 kernel/softirq.c:571 do_softirq+0xb1/0xf0 kernel/softirq.c:472 __local_bh_enable_ip+0x6f/0x80 kernel/softirq.c:396 __raw_read_unlock_bh include/linux/rwlock_api_smp.h:257 [inline] _raw_read_unlock_bh+0x17/0x20 kernel/locking/spinlock.c:284 wg_socket_send_skb_to_peer+0x107/0x120 drivers/net/wireguard/socket.c:184 wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline] wg_packet_tx_worker+0x142/0x360 drivers/net/wireguard/send.c:276 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289 worker_thread+0x618/0xa70 kernel/workqueue.c:2436 kthread+0x1a9/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
write to 0xffff88813e7ec108 of 8 bytes by interrupt on cpu 1: __xfrm_policy_check+0x6ae/0x17f0 net/xfrm/xfrm_policy.c:3664 __xfrm_policy_check2 include/net/xfrm.h:1174 [inline] xfrm_policy_check include/net/xfrm.h:1179 [inline] xfrm6_policy_check+0x2e9/0x320 include/net/xfrm.h:1189 udpv6_queue_rcv_one_skb+0x48/0xa30 net/ipv6/udp.c:703 udpv6_queue_rcv_skb+0x2d6/0x310 net/ipv6/udp.c:792 udp6_unicast_rcv_skb+0x16b/0x190 net/ipv6/udp.c:935 __udp6_lib_rcv+0x84b/0x9b0 net/ipv6/udp.c:1020 udpv6_rcv+0x4b/0x50 net/ipv6/udp.c:1133 ip6_protocol_deliver_rcu+0x99e/0x1020 net/ipv6/ip6_input.c:439 ip6_input_finish net/ipv6/ip6_input.c:484 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ip6_input+0xca/0x180 net/ipv6/ip6_input.c:493 dst_input include/net/dst.h:454 [inline] ip6_rcv_finish+0x1e9/0x2d0 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:302 [inline] ipv6_rcv+0x85/0x140 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core net/core/dev.c:5482 [inline] __netif_receive_skb+0x8b/0x1b0 net/core/dev.c:5596 process_backlog+0x23f/0x3b0 net/core/dev.c:5924 __napi_poll+0x65/0x390 net/core/dev.c:6485 napi_poll net/core/dev.c:6552 [inline] net_rx_action+0x37e/0x730 net/core/dev.c:6663 __do_softirq+0xf2/0x2c7 kernel/softirq.c:571 do_softirq+0xb1/0xf0 kernel/softirq.c:472 __local_bh_enable_ip+0x6f/0x80 kernel/softirq.c:396 __raw_read_unlock_bh include/linux/rwlock_api_smp.h:257 [inline] _raw_read_unlock_bh+0x17/0x20 kernel/locking/spinlock.c:284 wg_socket_send_skb_to_peer+0x107/0x120 drivers/net/wireguard/socket.c:184 wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline] wg_packet_tx_worker+0x142/0x360 drivers/net/wireguard/send.c:276 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289 worker_thread+0x618/0xa70 kernel/workqueue.c:2436 kthread+0x1a9/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
value changed: 0x0000000063c62d6f -> 0x0000000063c62d70
Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 4185 Comm: kworker/1:2 Tainted: G W 6.2.0-rc4-syzkaller-00009-gd532dd102151-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Steffen Klassert steffen.klassert@secunet.com Cc: Arnd Bergmann arnd@arndb.de Acked-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_policy.c | 11 +++++++---- net/xfrm/xfrm_state.c | 10 +++++----- 2 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index e392d8d05e0ca..52538d5360673 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -336,7 +336,7 @@ static void xfrm_policy_timer(struct timer_list *t) } if (xp->lft.hard_use_expires_seconds) { time64_t tmo = xp->lft.hard_use_expires_seconds + - (xp->curlft.use_time ? : xp->curlft.add_time) - now; + (READ_ONCE(xp->curlft.use_time) ? : xp->curlft.add_time) - now; if (tmo <= 0) goto expired; if (tmo < next) @@ -354,7 +354,7 @@ static void xfrm_policy_timer(struct timer_list *t) } if (xp->lft.soft_use_expires_seconds) { time64_t tmo = xp->lft.soft_use_expires_seconds + - (xp->curlft.use_time ? : xp->curlft.add_time) - now; + (READ_ONCE(xp->curlft.use_time) ? : xp->curlft.add_time) - now; if (tmo <= 0) { warn = 1; tmo = XFRM_KM_TIMEOUT; @@ -3586,7 +3586,8 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, return 1; }
- pol->curlft.use_time = ktime_get_real_seconds(); + /* This lockless write can happen from different cpus. */ + WRITE_ONCE(pol->curlft.use_time, ktime_get_real_seconds());
pols[0] = pol; npols++; @@ -3601,7 +3602,9 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, xfrm_pol_put(pols[0]); return 0; } - pols[1]->curlft.use_time = ktime_get_real_seconds(); + /* This write can happen from different cpus. */ + WRITE_ONCE(pols[1]->curlft.use_time, + ktime_get_real_seconds()); npols++; } } diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 3d2fe7712ac5b..0f88cb6fc3c22 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -572,7 +572,7 @@ static enum hrtimer_restart xfrm_timer_handler(struct hrtimer *me) } if (x->lft.hard_use_expires_seconds) { long tmo = x->lft.hard_use_expires_seconds + - (x->curlft.use_time ? : now) - now; + (READ_ONCE(x->curlft.use_time) ? : now) - now; if (tmo <= 0) goto expired; if (tmo < next) @@ -594,7 +594,7 @@ static enum hrtimer_restart xfrm_timer_handler(struct hrtimer *me) } if (x->lft.soft_use_expires_seconds) { long tmo = x->lft.soft_use_expires_seconds + - (x->curlft.use_time ? : now) - now; + (READ_ONCE(x->curlft.use_time) ? : now) - now; if (tmo <= 0) warn = 1; else if (tmo < next) @@ -1754,7 +1754,7 @@ int xfrm_state_update(struct xfrm_state *x)
hrtimer_start(&x1->mtimer, ktime_set(1, 0), HRTIMER_MODE_REL_SOFT); - if (x1->curlft.use_time) + if (READ_ONCE(x1->curlft.use_time)) xfrm_state_check_expire(x1);
if (x->props.smark.m || x->props.smark.v || x->if_id) { @@ -1786,8 +1786,8 @@ EXPORT_SYMBOL(xfrm_state_update);
int xfrm_state_check_expire(struct xfrm_state *x) { - if (!x->curlft.use_time) - x->curlft.use_time = ktime_get_real_seconds(); + if (!READ_ONCE(x->curlft.use_time)) + WRITE_ONCE(x->curlft.use_time, ktime_get_real_seconds());
if (x->curlft.bytes >= x->lft.hard_byte_limit || x->curlft.packets >= x->lft.hard_packet_limit) {