ddab82821f
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> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| bsd_comp.c | ||
| ppp_async.c | ||
| ppp_deflate.c | ||
| ppp_generic.c | ||
| ppp_mppe.c | ||
| ppp_mppe.h | ||
| ppp_synctty.c | ||
| pppoe.c | ||
| pppox.c | ||
| pptp.c | ||