Prior to commit 3f29cc82a84c ("nfsd: split sc_status out of
sc_type") states_show() relied on sc_type field to be of valid
type before calling into a subfunction to show content of a
particular stateid. From that commit, we split the validity of
the stateid into sc_status and no longer changed sc_type to 0
while unhashing the stateid. This resulted in kernel oopsing
for nfsv4.0 opens that stay around and in nfs4_show_open()
would derefence sc_file which was NULL.
Instead, for closed open stateids forgo displaying information
that relies of having a valid sc_file.
To reproduce: mount the server with 4.0, read and close
a file and then on the server cat /proc/fs/nfsd/clients/2/states
[ 513.590804] Call trace:
[ 513.590925] _raw_spin_lock+0xcc/0x160
[ 513.591119] nfs4_show_open+0x78/0x2c0 [nfsd]
[ 513.591412] states_show+0x44c/0x488 [nfsd]
[ 513.591681] seq_read_iter+0x5d8/0x760
[ 513.591896] seq_read+0x188/0x208
[ 513.592075] vfs_read+0x148/0x470
[ 513.592241] ksys_read+0xcc/0x178
Fixes: 3f29cc82a84c ("nfsd: split sc_status out of sc_type")
Signed-off-by: Olga Kornievskaia <okorniev@xxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c3def49074a4..2b1f8053b9c1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2786,15 +2786,18 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st)
deny & NFS4_SHARE_ACCESS_READ ? "r" : "-",
deny & NFS4_SHARE_ACCESS_WRITE ? "w" : "-");
- spin_lock(&nf->fi_lock);
- file = find_any_file_locked(nf);
- if (file) {
- nfs4_show_superblock(s, file);
- seq_puts(s, ", ");
- nfs4_show_fname(s, file);
- seq_puts(s, ", ");
- }
- spin_unlock(&nf->fi_lock);
+ if (nf) {
+ spin_lock(&nf->fi_lock);
+ file = find_any_file_locked(nf);
+ if (file) {
+ nfs4_show_superblock(s, file);
+ seq_puts(s, ", ");
+ nfs4_show_fname(s, file);
+ seq_puts(s, ", ");
+ }
+ spin_unlock(&nf->fi_lock);
+ } else
+ seq_puts(s, "closed, ");
nfs4_show_owner(s, oo);
if (st->sc_status & SC_STATUS_ADMIN_REVOKED)
seq_puts(s, ", admin-revoked");
--
2.43.5
