Hello NeilBrown,
Commit 11c3d0a15bbc ("nfsd: perform all find_openstateowner_str calls
in the one place.") from Mar 5, 2024 (linux-next), leads to the
following Smatch static checker warning:
fs/nfsd/nfs4state.c:1674 release_openowner()
warn: sleeping in atomic context
fs/nfsd/nfs4state.c
1657 static void release_openowner(struct nfs4_openowner *oo)
1658 {
1659 struct nfs4_ol_stateid *stp;
1660 struct nfs4_client *clp = oo->oo_owner.so_client;
1661 struct list_head reaplist;
1662
1663 INIT_LIST_HEAD(&reaplist);
1664
1665 spin_lock(&clp->cl_lock);
1666 unhash_openowner_locked(oo);
1667 while (!list_empty(&oo->oo_owner.so_stateids)) {
1668 stp = list_first_entry(&oo->oo_owner.so_stateids,
1669 struct nfs4_ol_stateid, st_perstateowner);
1670 if (unhash_open_stateid(stp, &reaplist))
1671 put_ol_stateid_locked(stp, &reaplist);
1672 }
1673 spin_unlock(&clp->cl_lock);
--> 1674 free_ol_stateid_reaplist(&reaplist);
^^^^^^^^^^^^^^^^^^^^^^^^
This is a might sleep function.
1675 release_last_closed_stateid(oo);
1676 nfs4_put_stateowner(&oo->oo_owner);
1677 }
The caller is find_or_alloc_open_stateowner()
fs/nfsd/nfs4state.c
4863 find_or_alloc_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
4864 struct nfsd4_compound_state *cstate)
4865 {
4866 struct nfs4_client *clp = cstate->clp;
4867 struct nfs4_openowner *oo, *new = NULL;
4868
4869 while (1) {
4870 spin_lock(&clp->cl_lock);
^^^^^^^^^^^^^^^^^^^^^^^^^
Huh... This looks like the same lock that we take in
release_openowner(). Why do I not see a static checker warning for
double lock?
4871 oo = find_openstateowner_str(strhashval, open, clp);
4872 if (oo && !(oo->oo_flags & NFS4_OO_CONFIRMED)) {
4873 /* Replace unconfirmed owners without checking for replay. */
4874 release_openowner(oo);
^^^^^^^^^^^^^^^^^^^^^^
Here
4875 oo = NULL;
4876 }
4877 if (oo) {
4878 spin_unlock(&clp->cl_lock);
4879 if (new)
4880 nfs4_free_stateowner(&new->oo_owner);
4881 return oo;
4882 }
4883 if (new) {
4884 hash_openowner(new, clp, strhashval);
4885 spin_unlock(&clp->cl_lock);
4886 return new;
4887 }
4888 spin_unlock(&clp->cl_lock);
regards,
dan carpenter
