From: Eric Dumazet edumazet@google.com
commit 550ac9c1aaaaf51fd42e20d461f0b1cdbd55b3d2 upstream.
syszbot triggers this warning, which looks something we can easily prevent.
If we initialize priv->list_field in chnl_net_init(), then always use list_del_init(), we can remove robust_list_del() completely.
WARNING: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 robust_list_del net/caif/chnl_net.c:67 [inline] WARNING: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375 Modules linked in: CPU: 0 PID: 3233 Comm: syz-executor.3 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:robust_list_del net/caif/chnl_net.c:67 [inline] RIP: 0010:chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375 Code: 89 eb e8 3a a3 ba f8 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 bf 01 00 00 48 81 fb 00 14 4e 8d 48 8b 2b 75 d0 e8 17 a3 ba f8 <0f> 0b 5b 5d 41 5c 41 5d e9 0a a3 ba f8 4c 89 e3 e8 02 a3 ba f8 4c RSP: 0018:ffffc90009067248 EFLAGS: 00010202 RAX: 0000000000008780 RBX: ffffffff8d4e1400 RCX: ffffc9000fd34000 RDX: 0000000000040000 RSI: ffffffff88bb6e49 RDI: 0000000000000003 RBP: ffff88802cd9ee08 R08: 0000000000000000 R09: ffffffff8d0e6647 R10: ffffffff88bb6dc2 R11: 0000000000000000 R12: ffff88803791ae08 R13: dffffc0000000000 R14: 00000000e600ffce R15: ffff888073ed3480 FS: 00007fed10fa0700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2c322000 CR3: 00000000164a6000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: register_netdevice+0xadf/0x1500 net/core/dev.c:10347 ipcaif_newlink+0x4c/0x260 net/caif/chnl_net.c:468 __rtnl_newlink+0x106d/0x1750 net/core/rtnetlink.c:3458 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3506 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 __sys_sendto+0x21c/0x320 net/socket.c:2036 __do_sys_sendto net/socket.c:2048 [inline] __se_sys_sendto net/socket.c:2044 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044 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
Fixes: cc36a070b590 ("net-caif: add CAIF netdevice") Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/caif/chnl_net.c | 19 +++---------------- 1 file changed, 3 insertions(+), 16 deletions(-)
--- a/net/caif/chnl_net.c +++ b/net/caif/chnl_net.c @@ -54,20 +54,6 @@ struct chnl_net { enum caif_states state; };
-static void robust_list_del(struct list_head *delete_node) -{ - struct list_head *list_node; - struct list_head *n; - ASSERT_RTNL(); - list_for_each_safe(list_node, n, &chnl_net_list) { - if (list_node == delete_node) { - list_del(list_node); - return; - } - } - WARN_ON(1); -} - static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt) { struct sk_buff *skb; @@ -369,6 +355,7 @@ static int chnl_net_init(struct net_devi ASSERT_RTNL(); priv = netdev_priv(dev); strncpy(priv->name, dev->name, sizeof(priv->name)); + INIT_LIST_HEAD(&priv->list_field); return 0; }
@@ -377,7 +364,7 @@ static void chnl_net_uninit(struct net_d struct chnl_net *priv; ASSERT_RTNL(); priv = netdev_priv(dev); - robust_list_del(&priv->list_field); + list_del_init(&priv->list_field); }
static const struct net_device_ops netdev_ops = { @@ -542,7 +529,7 @@ static void __exit chnl_exit_module(void rtnl_lock(); list_for_each_safe(list_node, _tmp, &chnl_net_list) { dev = list_entry(list_node, struct chnl_net, list_field); - list_del(list_node); + list_del_init(list_node); delete_device(dev); } rtnl_unlock();