Gao Feng ddab82821f ppp: Fix a scheduling-while-atomic bug in del_chan ... The PPTP set the pptp_sock_destruct as the sock's sk_destruct, it would trigger this bug when __sk_free is invoked in atomic context, because of the call path pptp_sock_destruct->del_chan->synchronize_rcu. Now move the synchronize_rcu to pptp_release from del_chan. This is the only one case which would free the sock and need the synchronize_rcu. The following is the panic I met with kernel 3.3.8, but this issue should exist in current kernel too according to the codes. BUG: scheduling while atomic __schedule_bug+0x5e/0x64 __schedule+0x55/0x580 ? ppp_unregister_channel+0x1cd5/0x1de0 [ppp_generic] ? dev_hard_start_xmit+0x423/0x530 ? sch_direct_xmit+0x73/0x170 __cond_resched+0x16/0x30 _cond_resched+0x22/0x30 wait_for_common+0x18/0x110 ? call_rcu_bh+0x10/0x10 wait_for_completion+0x12/0x20 wait_rcu_gp+0x34/0x40 ? wait_rcu_gp+0x40/0x40 synchronize_sched+0x1e/0x20 0xf8417298 0xf8417484 ? sock_queue_rcv_skb+0x109/0x130 __sk_free+0x16/0x110 ? udp_queue_rcv_skb+0x1f2/0x290 sk_free+0x16/0x20 __udp4_lib_rcv+0x3b8/0x650 Signed-off-by: Gao Feng <gfree.wind@vip.163.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-07-31 21:59:01 -07:00
..
bsd_comp.c
Kconfig
Makefile
ppp_async.c	networking: make skb_push & __skb_push return void pointers	2017-06-16 11:48:40 -04:00
ppp_deflate.c
ppp_generic.c	ppp: Fix false xmit recursion detect with two ppp devices	2017-07-18 11:20:33 -07:00
ppp_mppe.c	ppp: mppe: Use vsnprintf extension %phN	2017-06-06 15:16:33 -04:00
ppp_mppe.h
ppp_synctty.c	net: manual clean code which call skb_put_[data:zero]	2017-06-20 13:30:15 -04:00
pppoe.c	networking: make skb_put & friends return void pointers	2017-06-16 11:48:39 -04:00
pppox.c
pptp.c	ppp: Fix a scheduling-while-atomic bug in del_chan	2017-07-31 21:59:01 -07:00