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Fix a race on startup and another in the delegation code. The latter

Browse Source 
has been around for years, but I suspect recent changes may have
 widened the race window a little, so I'd like to go ahead and get it in.
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Merge tag 'nfsd-5.16-2' of git://linux-nfs.org/~bfields/linux

Pull nfsd fixes from Bruce Fields:
 "Fix a race on startup and another in the delegation code.

  The latter has been around for years, but I suspect recent changes may
  have widened the race window a little, so I'd like to go ahead and get
  it in"

* tag 'nfsd-5.16-2' of git://linux-nfs.org/~bfields/linux:
  nfsd: fix use-after-free due to delegation race
  nfsd: Fix nsfd startup race (again)
This commit is contained in:
Linus Torvalds
2021-12-10 17:17:53 -08:00
parent b9902641b5 548ec0805c
commit e80bdc5ed0
3 changed files with 15 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/nfsd/nfs4recover.c
View File

@ -2156,6 +2156,7 @@ static struct notifier_block nfsd4_cld_block = {
int
register_cld_notifier(void)
{
WARN_ON(!nfsd_net_id);
return rpc_pipefs_notifier_register(&nfsd4_cld_block);
}

9
fs/nfsd/nfs4state.c
View File

@ -1207,6 +1207,11 @@ hash_delegation_locked(struct nfs4_delegation *dp, struct nfs4_file *fp)
return 0;
}
static bool delegation_hashed(struct nfs4_delegation *dp)
{
return !(list_empty(&dp->dl_perfile));
}
static bool
unhash_delegation_locked(struct nfs4_delegation *dp)
{
@ -1214,7 +1219,7 @@ unhash_delegation_locked(struct nfs4_delegation *dp)
lockdep_assert_held(&state_lock);
if (list_empty(&dp->dl_perfile))
if (!delegation_hashed(dp))
return false;
dp->dl_stid.sc_type = NFS4_CLOSED_DELEG_STID;
@ -4598,7 +4603,7 @@ static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb)
* queued for a lease break. Don't queue it again.
*/
spin_lock(&state_lock);
if (dp->dl_time == 0) {
if (delegation_hashed(dp) && dp->dl_time == 0) {
dp->dl_time = ktime_get_boottime_seconds();
list_add_tail(&dp->dl_recall_lru, &nn->del_recall_lru);
}

14
fs/nfsd/nfsctl.c
View File

@ -1521,12 +1521,9 @@ static int __init init_nfsd(void)
int retval;
printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
retval = register_cld_notifier();
if (retval)
return retval;
retval = nfsd4_init_slabs();
if (retval)
goto out_unregister_notifier;
return retval;
retval = nfsd4_init_pnfs();
if (retval)
goto out_free_slabs;
@ -1545,9 +1542,14 @@ static int __init init_nfsd(void)
goto out_free_exports;
retval = register_pernet_subsys(&nfsd_net_ops);
if (retval < 0)
goto out_free_filesystem;
retval = register_cld_notifier();
if (retval)
goto out_free_all;
return 0;
out_free_all:
unregister_pernet_subsys(&nfsd_net_ops);
out_free_filesystem:
unregister_filesystem(&nfsd_fs_type);
out_free_exports:
remove_proc_entry("fs/nfs/exports", NULL);
@ -1561,13 +1563,12 @@ out_free_pnfs:
nfsd4_exit_pnfs();
out_free_slabs:
nfsd4_free_slabs();
out_unregister_notifier:
unregister_cld_notifier();
return retval;
}
static void __exit exit_nfsd(void)
{
unregister_cld_notifier();
unregister_pernet_subsys(&nfsd_net_ops);
nfsd_drc_slab_free();
remove_proc_entry("fs/nfs/exports", NULL);
@ -1577,7 +1578,6 @@ static void __exit exit_nfsd(void)
nfsd4_free_slabs();
nfsd4_exit_pnfs();
unregister_filesystem(&nfsd_fs_type);
unregister_cld_notifier();
}
MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");