ppp: defer netns reference release for ppp channel

Matt reported that we have a NULL pointer dereference
in ppp_pernet() from ppp_connect_channel(),
i.e. pch->chan_net is NULL.

This is due to that a parallel ppp_unregister_channel()
could happen while we are in ppp_connect_channel(), during
which pch->chan_net set to NULL. Since we need a reference
to net per channel, it makes sense to sync the refcnt
with the life time of the channel, therefore we should
release this reference when we destroy it.

Fixes: 1f461dcdd296 ("ppp: take reference on channels netns")
Reported-by: Matt Bennett <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: [email protected]
Cc: Guillaume Nault <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Reviewed-by: Cyrill Gorcunov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions