6.12-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Layton jlayton@kernel.org
commit 930b64ca0c511521f0abdd1d57ce52b2a6e3476b upstream.
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.c... Cc: stable@vger.kernel.org # v6.9 Signed-off-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfsctl.c | 9 ++++++++- fs/nfsd/stats.c | 4 ++-- fs/nfsd/stats.h | 2 +- 3 files changed, 11 insertions(+), 4 deletions(-)
I did not have any problem cherry-picking 930b64 onto v6.13.11. This built and ran some simple NFSD tests in my lab.
--- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -2244,8 +2244,14 @@ static __net_init int nfsd_net_init(stru 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++) @@ -2255,12 +2261,13 @@ static __net_init int nfsd_net_init(stru 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) 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: --- a/fs/nfsd/stats.c +++ b/fs/nfsd/stats.c @@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *se
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) --- a/fs/nfsd/stats.h +++ b/fs/nfsd/stats.h @@ -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)