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Message-ID: <CY4PR15MB1317AE9CF20E139CED8EEA959A5C0@CY4PR15MB1317.namprd15.prod.outlook.com>
Date: Thu, 5 Dec 2019 21:11:03 +0000
From: Jon Maloy <jon.maloy@...csson.com>
To: Taehee Yoo <ap420073@...il.com>,
"davem@...emloft.net" <davem@...emloft.net>,
"ying.xue@...driver.com" <ying.xue@...driver.com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH net] tipc: fix ordering of tipc module init and exit
routine
Hi Taehee,
Why didn't you move netlink_compat_stop() too?
///jon
> -----Original Message-----
> From: Taehee Yoo <ap420073@...il.com>
> Sent: 5-Dec-19 11:37
> To: davem@...emloft.net; Jon Maloy <jon.maloy@...csson.com>; ying.xue@...driver.com;
> netdev@...r.kernel.org
> Cc: ap420073@...il.com
> Subject: [PATCH net] tipc: fix ordering of tipc module init and exit routine
>
> In order to set/get/dump, the tipc uses the generic netlink
> infrastructure. So, when tipc module is inserted, init function
> calls genl_register_family().
> After genl_register_family(), set/get/dump commands are immediately
> allowed and these callbacks internally use the net_generic.
> net_generic is allocated by register_pernet_device() but this
> is called after genl_register_family() in the __init function.
> So, these callbacks would use un-initialized net_generic.
>
> Test commands:
> #SHELL1
> while :
> do
> modprobe tipc
> modprobe -rv tipc
> done
>
> #SHELL2
> while :
> do
> tipc link list
> done
>
> Splat looks like:
> [ 59.616322][ T2788] kasan: CONFIG_KASAN_INLINE enabled
> [ 59.617234][ T2788] kasan: GPF could be caused by NULL-ptr deref or user memory access
> [ 59.618398][ T2788] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
> [ 59.619389][ T2788] CPU: 3 PID: 2788 Comm: tipc Not tainted 5.4.0+ #194
> [ 59.620231][ T2788] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox
> 12/01/2006
> [ 59.621428][ T2788] RIP: 0010:tipc_bcast_get_broadcast_mode+0x131/0x310 [tipc]
> [ 59.622379][ T2788] Code: c7 c6 ef 8b 38 c0 65 ff 0d 84 83 c9 3f e8 d7 a5 f2 e3 48 8d bb 38 11 00 00 48
> b8 00 00 00 00
> [ 59.622550][ T2780] NET: Registered protocol family 30
> [ 59.624627][ T2788] RSP: 0018:ffff88804b09f578 EFLAGS: 00010202
> [ 59.624630][ T2788] RAX: dffffc0000000000 RBX: 0000000000000011 RCX: 000000008bc66907
> [ 59.624631][ T2788] RDX: 0000000000000229 RSI: 000000004b3cf4cc RDI: 0000000000001149
> [ 59.624633][ T2788] RBP: ffff88804b09f588 R08: 0000000000000003 R09: fffffbfff4fb3df1
> [ 59.624635][ T2788] R10: fffffbfff50318f8 R11: ffff888066cadc18 R12: ffffffffa6cc2f40
> [ 59.624637][ T2788] R13: 1ffff11009613eba R14: ffff8880662e9328 R15: ffff8880662e9328
> [ 59.624639][ T2788] FS: 00007f57d8f7b740(0000) GS:ffff88806cc00000(0000)
> knlGS:0000000000000000
> [ 59.624645][ T2788] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 59.625875][ T2780] tipc: Started in single node mode
> [ 59.626128][ T2788] CR2: 00007f57d887a8c0 CR3: 000000004b140002 CR4: 00000000000606e0
> [ 59.633991][ T2788] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 59.635195][ T2788] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 59.636478][ T2788] Call Trace:
> [ 59.637025][ T2788] tipc_nl_add_bc_link+0x179/0x1470 [tipc]
> [ 59.638219][ T2788] ? lock_downgrade+0x6e0/0x6e0
> [ 59.638923][ T2788] ? __tipc_nl_add_link+0xf90/0xf90 [tipc]
> [ 59.639533][ T2788] ? tipc_nl_node_dump_link+0x318/0xa50 [tipc]
> [ 59.640160][ T2788] ? mutex_lock_io_nested+0x1380/0x1380
> [ 59.640746][ T2788] tipc_nl_node_dump_link+0x4fd/0xa50 [tipc]
> [ 59.641356][ T2788] ? tipc_nl_node_reset_link_stats+0x340/0x340 [tipc]
> [ 59.642088][ T2788] ? __skb_ext_del+0x270/0x270
> [ 59.642594][ T2788] genl_lock_dumpit+0x85/0xb0
> [ 59.643050][ T2788] netlink_dump+0x49c/0xed0
> [ 59.643529][ T2788] ? __netlink_sendskb+0xc0/0xc0
> [ 59.644044][ T2788] ? __netlink_dump_start+0x190/0x800
> [ 59.644617][ T2788] ? __mutex_unlock_slowpath+0xd0/0x670
> [ 59.645177][ T2788] __netlink_dump_start+0x5a0/0x800
> [ 59.645692][ T2788] genl_rcv_msg+0xa75/0xe90
> [ 59.646144][ T2788] ? __lock_acquire+0xdfe/0x3de0
> [ 59.646692][ T2788] ? genl_family_rcv_msg_attrs_parse+0x320/0x320
> [ 59.647340][ T2788] ? genl_lock_dumpit+0xb0/0xb0
> [ 59.647821][ T2788] ? genl_unlock+0x20/0x20
> [ 59.648290][ T2788] ? genl_parallel_done+0xe0/0xe0
> [ 59.648787][ T2788] ? find_held_lock+0x39/0x1d0
> [ 59.649276][ T2788] ? genl_rcv+0x15/0x40
> [ 59.649722][ T2788] ? lock_contended+0xcd0/0xcd0
> [ 59.650296][ T2788] netlink_rcv_skb+0x121/0x350
> [ 59.650828][ T2788] ? genl_family_rcv_msg_attrs_parse+0x320/0x320
> [ 59.651491][ T2788] ? netlink_ack+0x940/0x940
> [ 59.651953][ T2788] ? lock_acquire+0x164/0x3b0
> [ 59.652449][ T2788] genl_rcv+0x24/0x40
> [ 59.652841][ T2788] netlink_unicast+0x421/0x600
> [ ... ]
>
> Fixes: 7e4369057806 ("tipc: fix a slab object leak")
> Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace")
> Signed-off-by: Taehee Yoo <ap420073@...il.com>
> ---
> net/tipc/core.c | 27 ++++++++++++++-------------
> 1 file changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/net/tipc/core.c b/net/tipc/core.c
> index 7532a00ac73d..f5a55c225742 100644
> --- a/net/tipc/core.c
> +++ b/net/tipc/core.c
> @@ -148,14 +148,6 @@ static int __init tipc_init(void)
> sysctl_tipc_rmem[1] = RCVBUF_DEF;
> sysctl_tipc_rmem[2] = RCVBUF_MAX;
>
> - err = tipc_netlink_start();
> - if (err)
> - goto out_netlink;
> -
> - err = tipc_netlink_compat_start();
> - if (err)
> - goto out_netlink_compat;
> -
> err = tipc_register_sysctl();
> if (err)
> goto out_sysctl;
> @@ -180,8 +172,21 @@ static int __init tipc_init(void)
> if (err)
> goto out_bearer;
>
> + err = tipc_netlink_start();
> + if (err)
> + goto out_netlink;
> +
> + err = tipc_netlink_compat_start();
> + if (err)
> + goto out_netlink_compat;
> +
> pr_info("Started in single node mode\n");
> return 0;
> +
> +out_netlink_compat:
> + tipc_netlink_stop();
> +out_netlink:
> + tipc_bearer_cleanup();
> out_bearer:
> unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
> out_register_pernet_subsys:
> @@ -193,22 +198,18 @@ static int __init tipc_init(void)
> out_pernet:
> tipc_unregister_sysctl();
> out_sysctl:
> - tipc_netlink_compat_stop();
> -out_netlink_compat:
> - tipc_netlink_stop();
> -out_netlink:
> pr_err("Unable to start in single node mode\n");
> return err;
> }
>
> static void __exit tipc_exit(void)
> {
> + tipc_netlink_stop();
> tipc_bearer_cleanup();
> unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
> unregister_pernet_device(&tipc_topsrv_net_ops);
> tipc_socket_stop();
> unregister_pernet_device(&tipc_net_ops);
> - tipc_netlink_stop();
> tipc_netlink_compat_stop();
> tipc_unregister_sysctl();
>
> --
> 2.17.1
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