On Wed, 15 May 2013, Alex Elder wrote: > An osd client has a red-black tree describing its osds, and > occasionally we would get crashes due to one of these trees tree > becoming corrupt somehow. > > The problem turned out to be that reset_changed_osds() was being > called without protection of the osd client request mutex. That > function would call __reset_osd() for any osd that had changed, and > __reset_osd() would call __remove_osd() for any osd with no > outstanding requests, and finally __remove_osd() would remove the > corresponding entry from the red-black tree. Thus, the tree was > getting modified without having any lock protection, and was > vulnerable to problems due to concurrent updates. > > This appears to be the only osd tree updating path that has this > problem. It can be fairly easily fixed by moving the call up > a few lines, to just before the request mutex gets dropped > in kick_requests(). > > This resolves: > http://tracker.ceph.com/issues/5043 > Signed-off-by: Alex Elder <[email protected]>
Reviewed-by: Sage Weil <[email protected]> > --- > net/ceph/osd_client.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c > index d5953b8..3a246a6 100644 > --- a/net/ceph/osd_client.c > +++ b/net/ceph/osd_client.c > @@ -1675,13 +1675,13 @@ static void kick_requests(struct ceph_osd_client > *osdc, int force_resend) > __register_request(osdc, req); > __unregister_linger_request(osdc, req); > } > + reset_changed_osds(osdc); > mutex_unlock(&osdc->request_mutex); > > if (needmap) { > dout("%d requests for down osds, need new map\n", needmap); > ceph_monc_request_next_osdmap(&osdc->client->monc); > } > - reset_changed_osds(osdc); > } > > > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
