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nfsd: don't ignore the return code of svc_proc_register() 

Currently, nfsd_proc_stat_init() ignores the return value of
svc_proc_register(). If the procfile creation fails, then the kernel
will WARN when it tries to remove the entry later.

Fix nfsd_proc_stat_init() to return the same type of pointer as
svc_proc_register(), and fix up nfsd_net_init() to check that and fail
the nfsd_net construction if it occurs.

svc_proc_register() can fail if the dentry can't be allocated, or if an
identical dentry already exists. The second case is pretty unlikely in
the nfsd_net construction codepath, so if this happens, return -ENOMEM.

Reported-by: syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/
Cc: stable@vger.kernel.org # v6.9
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
pull/1191/head
Jeff Layton 2025-02-06 13:12:13 -05:00 committed by Chuck Lever
parent 2ed4f6fe15
commit 930b64ca0c
3 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
fs/nfsd/nfsctl.c
View File

@ -2202,8 +2202,14 @@ static __net_init int nfsd_net_init(struct net *net)
NFSD_STATS_COUNTERS_NUM);
if (retval)
goto out_repcache_error;
memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));
nn->nfsd_svcstats.program = &nfsd_programs[0];
if (!nfsd_proc_stat_init(net)) {
retval = -ENOMEM;
goto out_proc_error;
}
for (i = 0; i < sizeof(nn->nfsd_versions); i++)
nn->nfsd_versions[i] = nfsd_support_version(i);
for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
@ -2213,13 +2219,14 @@ static __net_init int nfsd_net_init(struct net *net)
nfsd4_init_leases_net(nn);
get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
seqlock_init(&nn->writeverf_lock);
nfsd_proc_stat_init(net);
#if IS_ENABLED(CONFIG_NFS_LOCALIO)
spin_lock_init(&nn->local_clients_lock);
INIT_LIST_HEAD(&nn->local_clients);
#endif
return 0;
out_proc_error:
percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);
out_repcache_error:
nfsd_idmap_shutdown(net);
out_idmap_error:

4
fs/nfsd/stats.c
View File

@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *seq, void *v)
DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);
void nfsd_proc_stat_init(struct net *net)
struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);
}
void nfsd_proc_stat_shutdown(struct net *net)

2
fs/nfsd/stats.h
View File

@ -10,7 +10,7 @@
#include <uapi/linux/nfsd/stats.h>
#include <linux/percpu_counter.h>
void nfsd_proc_stat_init(struct net *net);
struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);
void nfsd_proc_stat_shutdown(struct net *net);
static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)