diff options
| author | Guillaume Nault <g.nault@alphalink.fr> | 2018-01-10 16:24:45 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-10-21 08:46:19 +0100 |
| commit | 2f3c2f0155a711b56e8ce72320f88d1a019746d7 (patch) | |
| tree | bd3750f7c28385e5dc45574f2470c57aadf11747 /Documentation | |
| parent | 6bf2b03aa461c35ec7bf724cafe3caa3792eaefd (diff) | |
ppp: unlock all_ppp_mutex before registering device
commit 0171c41835591e9aa2e384b703ef9a6ae367c610 upstream.
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: 8cb775bc0a34 ("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>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions