Hi Vlad, On Thu 08-01-09 11:56:28, Vlad Yasevich wrote: > Michal Hocko wrote: [...] > > However we are currently seeing another issue. It is not a crash (only > > process is killed with BUG message in the log - see attached) but it is > > the problem with module reference counting ( > > BUG_ON(module_refcount(module)==0) in __module_get is called). > > > > I am not sure whether this is a real problem, because we were able to > > trigger this only on _one_ testing configuration while other one is OK. > > > > I have checked all places where sctp decreases module reference count > > (sock_put) and it seems that all places are correctly balanced with > > sock_hold resp. __module_get: > > - sctp_association_init vs. sctp_association_destroy > > - sctp_association_migrate - put for old and hold for new > > - sctp_endpoint_int vs. sctp_endpoint_destroy > > - sctp_close - one artificial hold because of sk_common_release (which calls > > put) > > - one put balanced with sys_accept which calls __module_get > > > > And all sock_put corresponds to the current upstream. > > > > Do you have any idea or remember any problem in this area which could > > trigger this? > > > > It smells either as some misconfiguration of the testing system or > > another race condition or just I am overlooking something. > > > > > > Try this commit: 027f6e1ad32de32f9fe1c61d0f744e329e8acfd9 > SCTP: Fix a potential race between timers and receive path. Thanks for this tip, but the same result on the same testing machine. > > Also, what does lsmod tell you about the reference count on sctp module? It shown something like 48 when I asked tester about that. Do you want some finer grained values (with 1s interval). I understand that this value can change rapidly so it is very imprecise. I would like to give a try another test HW configuration on Monday (whether we are able to reproduce at all). > > -vlad Thanks for your help Best regards -- Michal Hocko L3 team SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
