6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislav Fomichev sdf@fomichev.me
[ Upstream commit 0349659fd72f662c054ff20d432559bfaa228ce4 ]
Cosmin reports the following locking issue:
# BUG: sleeping function called from invalid context at kernel/locking/mutex.c:275 # dump_stack_lvl+0x4f/0x60 # __might_resched+0xeb/0x140 # mutex_lock+0x1a/0x40 # dev_set_promiscuity+0x26/0x90 # __dev_set_promiscuity+0x85/0x170 # __dev_set_rx_mode+0x69/0xa0 # dev_uc_add+0x6d/0x80 # vlan_dev_open+0x5f/0x120 [8021q] # __dev_open+0x10c/0x2a0 # __dev_change_flags+0x1a4/0x210 # netif_change_flags+0x22/0x60 # do_setlink.isra.0+0xdb0/0x10f0 # rtnl_newlink+0x797/0xb00 # rtnetlink_rcv_msg+0x1cb/0x3f0 # netlink_rcv_skb+0x53/0x100 # netlink_unicast+0x273/0x3b0 # netlink_sendmsg+0x1f2/0x430
Which is similar to recent syzkaller reports in [0] and [1] and triggers because macsec does not advertise IFF_UNICAST_FLT although it has proper ndo_set_rx_mode callback that takes care of pushing uc/mc addresses down to the real device.
In general, dev_uc_add call path is problematic for stacking non-IFF_UNICAST_FLT because we might grab netdev instance lock under addr_list_lock spinlock, so this is not a systemic fix.
0: https://lore.kernel.org/netdev/686d55b4.050a0220.1ffab7.0014.GAE@google.com 1: https://lore.kernel.org/netdev/68712acf.a00a0220.26a83e.0051.GAE@google.com/ Reviewed-by: Simon Horman horms@kernel.org Tested-by: Simon Horman horms@kernel.org Link: https://lore.kernel.org/netdev/2aff4342b0f5b1539c02ffd8df4c7e58dd9746e7.came... Fixes: 7e4d784f5810 ("net: hold netdev instance lock during rtnetlink operations") Reported-by: Cosmin Ratiu cratiu@nvidia.com Tested-by: Cosmin Ratiu cratiu@nvidia.com Signed-off-by: Stanislav Fomichev sdf@fomichev.me Link: https://patch.msgid.link/20250723224715.1341121-1-sdf@fomichev.me Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/macsec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 7edbe76b5455..4c75d1fea552 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -3868,7 +3868,7 @@ static void macsec_setup(struct net_device *dev) ether_setup(dev); dev->min_mtu = 0; dev->max_mtu = ETH_MAX_MTU; - dev->priv_flags |= IFF_NO_QUEUE; + dev->priv_flags |= IFF_NO_QUEUE | IFF_UNICAST_FLT; dev->netdev_ops = &macsec_netdev_ops; dev->needs_free_netdev = true; dev->priv_destructor = macsec_free_netdev;