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linux/drivers/net/ppp
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Guillaume Nault 759cd103dd ppp: unlock all_ppp_mutex before registering device 
[ Upstream commit 0171c41835 ]

ppp_dev_uninit(), which is the .ndo_uninit() handler of PPP devices,
needs to lock pn->all_ppp_mutex. Therefore we mustn't call
register_netdevice() with pn->all_ppp_mutex already locked, or we'd
deadlock in case register_netdevice() fails and calls .ndo_uninit().

Fortunately, we can unlock pn->all_ppp_mutex before calling
register_netdevice(). This lock protects pn->units_idr, which isn't
used in the device registration process.

However, keeping pn->all_ppp_mutex locked during device registration
did ensure that no device in transient state would be published in
pn->units_idr. In practice, unlocking it before calling
register_netdevice() doesn't change this property: ppp_unit_register()
is called with 'ppp_mutex' locked and all searches done in
pn->units_idr hold this lock too.

Fixes: 8cb775bc0a ("ppp: fix device unregistration upon netns deletion")
Reported-and-tested-by: syzbot+367889b9c9e279219175@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-01-31 14:03:46 +01:00
..
bsd_comp.c ppp: Move the PPP drivers 2011-08-27 00:58:26 -07:00
Kconfig tty/serial patches for 3.9-rc1 2013-02-21 13:41:04 -08:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ppp_async.c networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
ppp_deflate.c ppp: deflate: never return len larger than output buffer 2015-01-29 14:50:01 -08:00
ppp_generic.c ppp: unlock all_ppp_mutex before registering device 2018-01-31 14:03:46 +01:00
ppp_mppe.c ppp: mppe: Use vsnprintf extension %phN 2017-06-06 15:16:33 -04:00
ppp_mppe.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ppp_synctty.c net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
pppoe.c pppoe: take ->needed_headroom of lower device into account on xmit 2018-01-31 14:03:45 +01:00
pppox.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pptp.c ppp: Fix a scheduling-while-atomic bug in del_chan 2017-07-31 21:59:01 -07:00