From: Eric Dumazet edumazet@google.com
commit dac8e00fb640e9569cdeefd3ce8a75639e5d0711 upstream.
KCSAN reported a data-race [1] around tx_rebalance_counter which can be accessed from different contexts, without the protection of a lock/mutex.
[1] BUG: KCSAN: data-race in bond_alb_init_slave / bond_alb_monitor
write to 0xffff888157e8ca24 of 4 bytes by task 7075 on cpu 0: bond_alb_init_slave+0x713/0x860 drivers/net/bonding/bond_alb.c:1613 bond_enslave+0xd94/0x3010 drivers/net/bonding/bond_main.c:1949 do_set_master net/core/rtnetlink.c:2521 [inline] __rtnl_newlink net/core/rtnetlink.c:3475 [inline] rtnl_newlink+0x1298/0x13b0 net/core/rtnetlink.c:3506 rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5571 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2491 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5589 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x5fc/0x6c0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x6e1/0x7d0 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmsg+0x195/0x230 net/socket.c:2492 __do_sys_sendmsg net/socket.c:2501 [inline] __se_sys_sendmsg net/socket.c:2499 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2499 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff888157e8ca24 of 4 bytes by task 1082 on cpu 1: bond_alb_monitor+0x8f/0xc00 drivers/net/bonding/bond_alb.c:1511 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298 worker_thread+0x616/0xa70 kernel/workqueue.c:2445 kthread+0x2c7/0x2e0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30
value changed: 0x00000001 -> 0x00000064
Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 1082 Comm: kworker/u4:3 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bond1 bond_alb_monitor
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_alb.c | 14 ++++++++------ include/net/bond_alb.h | 2 +- 2 files changed, 9 insertions(+), 7 deletions(-)
--- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -1514,14 +1514,14 @@ void bond_alb_monitor(struct work_struct struct slave *slave;
if (!bond_has_slaves(bond)) { - bond_info->tx_rebalance_counter = 0; + atomic_set(&bond_info->tx_rebalance_counter, 0); bond_info->lp_counter = 0; goto re_arm; }
rcu_read_lock();
- bond_info->tx_rebalance_counter++; + atomic_inc(&bond_info->tx_rebalance_counter); bond_info->lp_counter++;
/* send learning packets */ @@ -1543,7 +1543,7 @@ void bond_alb_monitor(struct work_struct }
/* rebalance tx traffic */ - if (bond_info->tx_rebalance_counter >= BOND_TLB_REBALANCE_TICKS) { + if (atomic_read(&bond_info->tx_rebalance_counter) >= BOND_TLB_REBALANCE_TICKS) { bond_for_each_slave_rcu(bond, slave, iter) { tlb_clear_slave(bond, slave, 1); if (slave == rcu_access_pointer(bond->curr_active_slave)) { @@ -1553,7 +1553,7 @@ void bond_alb_monitor(struct work_struct bond_info->unbalanced_load = 0; } } - bond_info->tx_rebalance_counter = 0; + atomic_set(&bond_info->tx_rebalance_counter, 0); }
if (bond_info->rlb_enabled) { @@ -1623,7 +1623,8 @@ int bond_alb_init_slave(struct bonding * tlb_init_slave(slave);
/* order a rebalance ASAP */ - bond->alb_info.tx_rebalance_counter = BOND_TLB_REBALANCE_TICKS; + atomic_set(&bond->alb_info.tx_rebalance_counter, + BOND_TLB_REBALANCE_TICKS);
if (bond->alb_info.rlb_enabled) bond->alb_info.rlb_rebalance = 1; @@ -1660,7 +1661,8 @@ void bond_alb_handle_link_change(struct rlb_clear_slave(bond, slave); } else if (link == BOND_LINK_UP) { /* order a rebalance ASAP */ - bond_info->tx_rebalance_counter = BOND_TLB_REBALANCE_TICKS; + atomic_set(&bond_info->tx_rebalance_counter, + BOND_TLB_REBALANCE_TICKS); if (bond->alb_info.rlb_enabled) { bond->alb_info.rlb_rebalance = 1; /* If the updelay module parameter is smaller than the --- a/include/net/bond_alb.h +++ b/include/net/bond_alb.h @@ -126,7 +126,7 @@ struct tlb_slave_info { struct alb_bond_info { struct tlb_client_info *tx_hashtbl; /* Dynamically allocated */ u32 unbalanced_load; - int tx_rebalance_counter; + atomic_t tx_rebalance_counter; int lp_counter; /* -------- rlb parameters -------- */ int rlb_enabled;