diff options
| author |   Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-06-15 13:02:58 -0400 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-06-19 13:32:45 -0400 |
| commit | 0a9c63fae7df086ff5e107273c3cce8642430974 (patch) | |
| tree | a8636a5d35f0ae5e45f64d27759dd02d7e2ca598 /fs | |
| parent | NFSv4.1: Fix umount when filelayout DS is also the MDS (diff) | |
| download | linux-dev-0a9c63fae7df086ff5e107273c3cce8642430974.tar.xz linux-dev-0a9c63fae7df086ff5e107273c3cce8642430974.zip | |
NFSv4.1: Fix a race in set_pnfs_layoutdriver
The call to try_module_get() dereferences ld_type outside the
spin locks, which means that it may be pointing to garbage if
a module unload was in progress.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/pnfs.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index bdf7e52943c8..bbc49caa7a82 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -70,6 +70,10 @@ find_pnfs_driver(u32 id) spin_lock(&pnfs_spinlock); local = find_pnfs_driver_locked(id); + if (local != NULL && !try_module_get(local->owner)) { + dprintk("%s: Could not grab reference on module\n", __func__); + local = NULL; + } spin_unlock(&pnfs_spinlock); return local; } @@ -118,10 +122,6 @@ set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh, goto out_no_driver; } } - if (!try_module_get(ld_type->owner)) { - dprintk("%s: Could not grab reference on module\n", __func__); - goto out_no_driver; - } server->pnfs_curr_ld = ld_type; if (ld_type->set_layoutdriver && ld_type->set_layoutdriver(server, mntfh)) { |