[MPTCP][PATCH net] mptcp: fix kmalloc flag in mptcp_pm_nl_get_local_id

From: Geliang Tang
Date: Tue Sep 08 2020 - 23:03:52 EST


mptcp_pm_nl_get_local_id may be called in interrupt context, so we need to
use GFP_ATOMIC flag to allocate memory to avoid sleeping in atomic context.

[ 280.209809] BUG: sleeping function called from invalid context at mm/slab.h:498
[ 280.209812] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1680, name: kworker/1:3
[ 280.209814] INFO: lockdep is turned off.
[ 280.209816] CPU: 1 PID: 1680 Comm: kworker/1:3 Tainted: G W 5.9.0-rc3-mptcp+ #146
[ 280.209818] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 280.209820] Workqueue: events mptcp_worker
[ 280.209822] Call Trace:
[ 280.209824] <IRQ>
[ 280.209826] dump_stack+0x77/0xa0
[ 280.209829] ___might_sleep.cold+0xa6/0xb6
[ 280.209832] kmem_cache_alloc_trace+0x1d1/0x290
[ 280.209835] mptcp_pm_nl_get_local_id+0x23c/0x410
[ 280.209840] subflow_init_req+0x1e9/0x2ea
[ 280.209843] ? inet_reqsk_alloc+0x1c/0x120
[ 280.209845] ? kmem_cache_alloc+0x264/0x290
[ 280.209849] tcp_conn_request+0x303/0xae0
[ 280.209854] ? printk+0x53/0x6a
[ 280.209857] ? tcp_rcv_state_process+0x28f/0x1374
[ 280.209859] tcp_rcv_state_process+0x28f/0x1374
[ 280.209864] ? tcp_v4_do_rcv+0xb3/0x1f0
[ 280.209866] tcp_v4_do_rcv+0xb3/0x1f0
[ 280.209869] tcp_v4_rcv+0xed6/0xfa0
[ 280.209873] ip_protocol_deliver_rcu+0x28/0x270
[ 280.209875] ip_local_deliver_finish+0x89/0x120
[ 280.209877] ip_local_deliver+0x180/0x220
[ 280.209881] ip_rcv+0x166/0x210
[ 280.209885] __netif_receive_skb_one_core+0x82/0x90
[ 280.209888] process_backlog+0xd6/0x230
[ 280.209891] net_rx_action+0x13a/0x410
[ 280.209895] __do_softirq+0xcf/0x468
[ 280.209899] asm_call_on_stack+0x12/0x20
[ 280.209901] </IRQ>
[ 280.209903] ? ip_finish_output2+0x240/0x9a0
[ 280.209906] do_softirq_own_stack+0x4d/0x60
[ 280.209908] do_softirq.part.0+0x2b/0x60
[ 280.209911] __local_bh_enable_ip+0x9a/0xa0
[ 280.209913] ip_finish_output2+0x264/0x9a0
[ 280.209916] ? rcu_read_lock_held+0x4d/0x60
[ 280.209920] ? ip_output+0x7a/0x250
[ 280.209922] ip_output+0x7a/0x250
[ 280.209925] ? __ip_finish_output+0x330/0x330
[ 280.209928] __ip_queue_xmit+0x1dc/0x5a0
[ 280.209931] __tcp_transmit_skb+0xa0f/0xc70
[ 280.209937] tcp_connect+0xb03/0xff0
[ 280.209939] ? lockdep_hardirqs_on_prepare+0xe7/0x190
[ 280.209942] ? ktime_get_with_offset+0x125/0x150
[ 280.209944] ? trace_hardirqs_on+0x1c/0xe0
[ 280.209948] tcp_v4_connect+0x449/0x550
[ 280.209953] __inet_stream_connect+0xbb/0x320
[ 280.209955] ? mark_held_locks+0x49/0x70
[ 280.209958] ? lockdep_hardirqs_on_prepare+0xe7/0x190
[ 280.209960] ? __local_bh_enable_ip+0x6b/0xa0
[ 280.209963] inet_stream_connect+0x32/0x50
[ 280.209966] __mptcp_subflow_connect+0x1fd/0x242
[ 280.209972] mptcp_pm_create_subflow_or_signal_addr+0x2db/0x600
[ 280.209975] mptcp_worker+0x543/0x7a0
[ 280.209980] process_one_work+0x26d/0x5b0
[ 280.209984] ? process_one_work+0x5b0/0x5b0
[ 280.209987] worker_thread+0x48/0x3d0
[ 280.209990] ? process_one_work+0x5b0/0x5b0
[ 280.209993] kthread+0x117/0x150
[ 280.209996] ? kthread_park+0x80/0x80
[ 280.209998] ret_from_fork+0x22/0x30

Fixes: 01cacb00b35cb ("mptcp: add netlink-based PM")
Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>
---
net/mptcp/pm_netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index bd88e9c0bf71..1f6d029ccf40 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -354,7 +354,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
return ret;

/* address not found, add to local list */
- entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
if (!entry)
return -ENOMEM;

--
2.17.1