09.05.2012 18:26, J. Bruce Fields написал:
Reviewing your more recent patches I think we have a problem with some
of the code that's already merged. See the comment in svc_shutdown_net:
void svc_shutdown_net(struct svc_serv *serv, struct net *net)
{
/*
* The set of xprts (contained in the sv_tempsocks and
* sv_permsocks lists) is now constant, since it is modified
* only by accepting new sockets (done by service threads in
* svc_recv) or aging old ones (done by sv_temptimer), or
* configuration changes (excluded by whatever locking the
* caller is using--nfsd_mutex in the case of nfsd). So it's
* safe to traverse those lists and shut everything down:
*/
svc_close_net(serv, net);
if (serv->sv_shutdown)
serv->sv_shutdown(serv, net);
}
So we depend on the fact that neither the server threads nor
sv_temptimer are running here to be able to safely traverse those lists
of sockets.
But it looks to me like that's no longer true--we're shutting down just
one namespace here, and others may still be running. If so and if they
modify sv_tempsocks or sv_permsocks while we're running through them
then we're going to get a crash.
Yes, you right. Thanks. I missed this.
You made some changes prior to my patches, which allowed to remove
locking on these lists,if i'm not mistaken.
Anyway, read-write lock should be enough here, I suppose (I don't have
sources right now to investigate) ?
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