race of nfsd inetaddr notifiers vs nn->nfsd_serv change
authorVasily Averin <vvs@virtuozzo.com>
Fri, 10 Nov 2017 07:19:35 +0000 (10:19 +0300)
committerJ. Bruce Fields <bfields@redhat.com>
Mon, 27 Nov 2017 21:45:11 +0000 (16:45 -0500)
commit2317dc557a3b6d5b73b697034611d658eb2cbde9
tree9854e4dff8bb6981a73aca72427187d3afea4d52
parent6b18dd1c03e07262ea0866084856b2a3c5ba8d09
race of nfsd inetaddr notifiers vs nn->nfsd_serv change

nfsd_inet[6]addr_event uses nn->nfsd_serv without taking nfsd_mutex,
which can be changed during execution of notifiers and crash the host.

Moreover if notifiers were enabled in one net namespace they are enabled
in all other net namespaces, from creation until destruction.

This patch allows notifiers to access nn->nfsd_serv only after the
pointer is correctly initialized and delays cleanup until notifiers are
no longer in use.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Tested-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
fs/nfsd/netns.h
fs/nfsd/nfsctl.c
fs/nfsd/nfssvc.c