@@ -5591,16 +5591,20 @@ static int bond_ethtool_get_ts_info(struct net_device *bond_dev,
const struct ethtool_ops *ops;
struct net_device *real_dev;
struct phy_device *phydev;
+ int ret = 0;
+ rcu_read_lock();
real_dev = bond_option_active_slave_get_rcu(bond);
if (real_dev) {
ops = real_dev->ethtool_ops;
phydev = real_dev->phydev;
if (phy_has_tsinfo(phydev)) {
- return phy_ts_info(phydev, info);
+ ret = phy_ts_info(phydev, info);
+ goto out;
} else if (ops->get_ts_info) {
- return ops->get_ts_info(real_dev, info);
+ ret = ops->get_ts_info(real_dev, info);
+ goto out;
}
}
@@ -5608,7 +5612,9 @@ static int bond_ethtool_get_ts_info(struct net_device *bond_dev,
SOF_TIMESTAMPING_SOFTWARE;
info->phc_index = -1;
- return 0;
+out:
+ rcu_read_unlock();
+ return ret;
}
static const struct ethtool_ops bond_ethtool_ops = {
When removing the rcu_read_lock in bond_ethtool_get_ts_info(), I didn't notice it could be called via setsockopt, which doesn't hold rcu lock, as syzbot pointed: stack backtrace: CPU: 0 PID: 3599 Comm: syz-executor317 Not tainted 5.18.0-rc5-syzkaller-01392-g01f4685797a5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 bond_option_active_slave_get_rcu include/net/bonding.h:353 [inline] bond_ethtool_get_ts_info+0x32c/0x3a0 drivers/net/bonding/bond_main.c:5595 __ethtool_get_ts_info+0x173/0x240 net/ethtool/common.c:554 ethtool_get_phc_vclocks+0x99/0x110 net/ethtool/common.c:568 sock_timestamping_bind_phc net/core/sock.c:869 [inline] sock_set_timestamping+0x3a3/0x7e0 net/core/sock.c:916 sock_setsockopt+0x543/0x2ec0 net/core/sock.c:1221 __sys_setsockopt+0x55e/0x6a0 net/socket.c:2223 __do_sys_setsockopt net/socket.c:2238 [inline] __se_sys_setsockopt net/socket.c:2235 [inline] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2235 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8902c8eb39 Fix it by adding rcu_read_lock during the whole slave dev get_ts_info period. Reported-by: syzbot+92beb3d46aab498710fa@syzkaller.appspotmail.com Fixes: aa6034678e87 ("bonding: use rcu_dereference_rtnl when get bonding active slave") Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> --- drivers/net/bonding/bond_main.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)