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| author | Mike Snitzer <snitzer@kernel.org> | 2024-10-03 15:34:58 -0400 |
|---|---|---|
| committer | Anna Schumaker <anna.schumaker@oracle.com> | 2024-10-03 16:19:43 -0400 |
| commit | 65f2a5c366353da6fa724c68347e1de954928143 (patch) | |
| tree | 3dbc942931e5b9c55c54519e9fcf846b841cd8be /fs/nfsd/nfssvc.c | |
| parent | a848c29e3486189aaabd5663bc11aea50c5bd144 (diff) | |
| download | linux-65f2a5c366353da6fa724c68347e1de954928143.tar.gz linux-65f2a5c366353da6fa724c68347e1de954928143.tar.bz2 linux-65f2a5c366353da6fa724c68347e1de954928143.zip | |
nfs_common: fix race in NFS calls to nfsd_file_put_local() and nfsd_serv_put()
Add nfs_to_nfsd_file_put_local() interface to fix race with nfsd
module unload. Similarly, use RCU around nfs_open_local_fh()'s error
path call to nfs_to->nfsd_serv_put(). Holding RCU ensures that NFS
will safely _call and return_ from its nfs_to calls into the NFSD
functions nfsd_file_put_local() and nfsd_serv_put().
Otherwise, if RCU isn't used then there is a narrow window when NFS's
reference for the nfsd_file and nfsd_serv are dropped and the NFSD
module could be unloaded, which could result in a crash from the
return instruction for either nfs_to->nfsd_file_put_local() or
nfs_to->nfsd_serv_put().
Reported-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Diffstat (limited to 'fs/nfsd/nfssvc.c')
| -rw-r--r-- | fs/nfsd/nfssvc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index e236135ddc63..47172b407be8 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -214,14 +214,14 @@ int nfsd_minorversion(struct nfsd_net *nn, u32 minorversion, enum vers_op change return 0; } -bool nfsd_serv_try_get(struct net *net) +bool nfsd_serv_try_get(struct net *net) __must_hold(rcu) { struct nfsd_net *nn = net_generic(net, nfsd_net_id); return (nn && percpu_ref_tryget_live(&nn->nfsd_serv_ref)); } -void nfsd_serv_put(struct net *net) +void nfsd_serv_put(struct net *net) __must_hold(rcu) { struct nfsd_net *nn = net_generic(net, nfsd_net_id); |