From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>,
Andy Gospodarek <andy@greyhouse.net>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>,
syzbot <syzkaller@googlegroups.com>
Subject: [PATCH v2 net] bonding: annotate data-races around slave->last_rx
Date: Thu, 22 Jan 2026 16:29:14 +0000 [thread overview]
Message-ID: <20260122162914.2299312-1-edumazet@google.com> (raw)
slave->last_rx and slave->target_last_arp_rx[...] can be read and written
locklessly. Add READ_ONCE() and WRITE_ONCE() annotations.
syzbot reported:
BUG: KCSAN: data-race in bond_rcv_validate / bond_rcv_validate
write to 0xffff888149f0d428 of 8 bytes by interrupt on cpu 1:
bond_rcv_validate+0x202/0x7a0 drivers/net/bonding/bond_main.c:3335
bond_handle_frame+0xde/0x5e0 drivers/net/bonding/bond_main.c:1533
__netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039
__netif_receive_skb_one_core net/core/dev.c:6150 [inline]
__netif_receive_skb+0x59/0x270 net/core/dev.c:6265
netif_receive_skb_internal net/core/dev.c:6351 [inline]
netif_receive_skb+0x4b/0x2d0 net/core/dev.c:6410
...
write to 0xffff888149f0d428 of 8 bytes by interrupt on cpu 0:
bond_rcv_validate+0x202/0x7a0 drivers/net/bonding/bond_main.c:3335
bond_handle_frame+0xde/0x5e0 drivers/net/bonding/bond_main.c:1533
__netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039
__netif_receive_skb_one_core net/core/dev.c:6150 [inline]
__netif_receive_skb+0x59/0x270 net/core/dev.c:6265
netif_receive_skb_internal net/core/dev.c:6351 [inline]
netif_receive_skb+0x4b/0x2d0 net/core/dev.c:6410
br_netif_receive_skb net/bridge/br_input.c:30 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
...
value changed: 0x0000000100005365 -> 0x0000000100005366
Fixes: f5b2b966f032 ("[PATCH] bonding: Validate probe replies in ARP monitor")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
---
v2: Addressed AI feedback about _bond_options_ns_ip6_target_set()
Added {READ,WRITEE_ONCE() in bond_option_arp_ip_target_rem()
v1: https://lore.kernel.org/netdev/20260120152856.1694824-1-edumazet@google.com/
drivers/net/bonding/bond_main.c | 18 ++++++++++--------
drivers/net/bonding/bond_options.c | 8 ++++----
include/net/bonding.h | 13 +++++++------
3 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index e7caf400a59cbd9680adea3d1b8ab7a22c78f7e6..a909ebcf1102d46beadc216a1b1a8a10e227ecb4 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3047,8 +3047,8 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
__func__, &sip);
return;
}
- slave->last_rx = jiffies;
- slave->target_last_arp_rx[i] = jiffies;
+ WRITE_ONCE(slave->last_rx, jiffies);
+ WRITE_ONCE(slave->target_last_arp_rx[i], jiffies);
}
static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
@@ -3267,8 +3267,8 @@ static void bond_validate_na(struct bonding *bond, struct slave *slave,
__func__, saddr);
return;
}
- slave->last_rx = jiffies;
- slave->target_last_arp_rx[i] = jiffies;
+ WRITE_ONCE(slave->last_rx, jiffies);
+ WRITE_ONCE(slave->target_last_arp_rx[i], jiffies);
}
static int bond_na_rcv(const struct sk_buff *skb, struct bonding *bond,
@@ -3338,7 +3338,7 @@ int bond_rcv_validate(const struct sk_buff *skb, struct bonding *bond,
(slave_do_arp_validate_only(bond) && is_ipv6) ||
#endif
!slave_do_arp_validate_only(bond))
- slave->last_rx = jiffies;
+ WRITE_ONCE(slave->last_rx, jiffies);
return RX_HANDLER_ANOTHER;
} else if (is_arp) {
return bond_arp_rcv(skb, bond, slave);
@@ -3406,7 +3406,7 @@ static void bond_loadbalance_arp_mon(struct bonding *bond)
if (slave->link != BOND_LINK_UP) {
if (bond_time_in_interval(bond, last_tx, 1) &&
- bond_time_in_interval(bond, slave->last_rx, 1)) {
+ bond_time_in_interval(bond, READ_ONCE(slave->last_rx), 1)) {
bond_propose_link_state(slave, BOND_LINK_UP);
slave_state_changed = 1;
@@ -3430,8 +3430,10 @@ static void bond_loadbalance_arp_mon(struct bonding *bond)
* when the source ip is 0, so don't take the link down
* if we don't know our ip yet
*/
- if (!bond_time_in_interval(bond, last_tx, bond->params.missed_max) ||
- !bond_time_in_interval(bond, slave->last_rx, bond->params.missed_max)) {
+ if (!bond_time_in_interval(bond, last_tx,
+ bond->params.missed_max) ||
+ !bond_time_in_interval(bond, READ_ONCE(slave->last_rx),
+ bond->params.missed_max)) {
bond_propose_link_state(slave, BOND_LINK_DOWN);
slave_state_changed = 1;
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 384499c869b8da9f036c43eb081095f1bf2141af..f1c6e9d8f61671e817bb417af39271dc14dd7bd9 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -1152,7 +1152,7 @@ static void _bond_options_arp_ip_target_set(struct bonding *bond, int slot,
if (slot >= 0 && slot < BOND_MAX_ARP_TARGETS) {
bond_for_each_slave(bond, slave, iter)
- slave->target_last_arp_rx[slot] = last_rx;
+ WRITE_ONCE(slave->target_last_arp_rx[slot], last_rx);
targets[slot] = target;
}
}
@@ -1221,8 +1221,8 @@ static int bond_option_arp_ip_target_rem(struct bonding *bond, __be32 target)
bond_for_each_slave(bond, slave, iter) {
targets_rx = slave->target_last_arp_rx;
for (i = ind; (i < BOND_MAX_ARP_TARGETS-1) && targets[i+1]; i++)
- targets_rx[i] = targets_rx[i+1];
- targets_rx[i] = 0;
+ WRITE_ONCE(targets_rx[i], READ_ONCE(targets_rx[i+1]));
+ WRITE_ONCE(targets_rx[i], 0);
}
for (i = ind; (i < BOND_MAX_ARP_TARGETS-1) && targets[i+1]; i++)
targets[i] = targets[i+1];
@@ -1377,7 +1377,7 @@ static void _bond_options_ns_ip6_target_set(struct bonding *bond, int slot,
if (slot >= 0 && slot < BOND_MAX_NS_TARGETS) {
bond_for_each_slave(bond, slave, iter) {
- slave->target_last_arp_rx[slot] = last_rx;
+ WRITE_ONCE(slave->target_last_arp_rx[slot], last_rx);
slave_set_ns_maddr(bond, slave, target, &targets[slot]);
}
targets[slot] = *target;
diff --git a/include/net/bonding.h b/include/net/bonding.h
index 49edc7da05867f355f880329817bdc2a371f226b..46207840355709ee28d771c803b8ee6ef8920538 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -521,13 +521,14 @@ static inline int bond_is_ip6_target_ok(struct in6_addr *addr)
static inline unsigned long slave_oldest_target_arp_rx(struct bonding *bond,
struct slave *slave)
{
+ unsigned long tmp, ret = READ_ONCE(slave->target_last_arp_rx[0]);
int i = 1;
- unsigned long ret = slave->target_last_arp_rx[0];
-
- for (; (i < BOND_MAX_ARP_TARGETS) && bond->params.arp_targets[i]; i++)
- if (time_before(slave->target_last_arp_rx[i], ret))
- ret = slave->target_last_arp_rx[i];
+ for (; (i < BOND_MAX_ARP_TARGETS) && bond->params.arp_targets[i]; i++) {
+ tmp = READ_ONCE(slave->target_last_arp_rx[i]);
+ if (time_before(tmp, ret))
+ ret = tmp;
+ }
return ret;
}
@@ -537,7 +538,7 @@ static inline unsigned long slave_last_rx(struct bonding *bond,
if (bond->params.arp_all_targets == BOND_ARP_TARGETS_ALL)
return slave_oldest_target_arp_rx(bond, slave);
- return slave->last_rx;
+ return READ_ONCE(slave->last_rx);
}
static inline void slave_update_last_tx(struct slave *slave)
--
2.52.0.457.g6b5491de43-goog
next reply other threads:[~2026-01-22 16:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-22 16:29 Eric Dumazet [this message]
2026-01-25 21:20 ` [PATCH v2 net] bonding: annotate data-races around slave->last_rx patchwork-bot+netdevbpf
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