We had someone report a bug against Fedora that they were seeing very high module reference counts for some krb5 related modules on his nfs server. For instance: # lsmod Module Size Used by des_generic 25216 52736 cbc 12160 52736 rpcsec_gss_krb5 15632 26370 ...the cbc and des_generic each have roughly 2 module references per rpcsec_gss_krb5 refcount so I'm assuming that the "lynchpin" here is the rpcsec_gss_krb5 refcount which seems to be increasing w/o bound. I've been able to reproduce this fairly easily by setting up a nfs server with a krb5 authenticated export. If I then mount that and immediately unmount it from a client, the refcount on rpcsec_gss_krb5 on the server increases by 1. For instance: First mount and unmount: Module Size Used by cbc 12288 2 rpcsec_gss_krb5 19208 1 des_generic 25344 2 Second mount and unmount: Module Size Used by cbc 12288 4 rpcsec_gss_krb5 19208 2 des_generic 25344 4 Third mount and unmount: Module Size Used by cbc 12288 6 rpcsec_gss_krb5 19208 3 des_generic 25344 6 ...while that's an easy way to reproduce it, there may be other ways to make it grow. Some printk debugging shows that the references are increased as a result of rsc_parse(). From my (rather naive) look at this code, it looks like each entry in the rsc_cache holds a module reference. I'm guessing that when these cache entries are released that the module references also get released, but I haven't been successful in making that occur. It seems like the module references are never put, so either the entries are never getting flushed out of the cache or the module references aren't being properly released by this code. There's no "content" file for this cache though, so it's hard to tell whether the cache is populated at any given time. Either way, this seems likely to be a bug. There doesn't seem to be a way to make the refcounts go down again once they've been increased. Can anyone confirm whether this is working as intended? If not, do you have any idea where the problem may be, or how to approach tracking this down? Unfortunately, I'm finding this code to be very hard to follow. Any help or suggestions appreciated... Thanks, -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
