We load nfsd module in the docker container, kernel crash as following.
The 'current->nsproxy->net_ns->gen->ptr[nfsd_net_id]' is overflow in the
nfsd_init_net.
We should use the net_ns which is being init in the nfsd_init_net,
not the 'current->nsproxy->net_ns'.
[ 939.174448] Installing knfsd (copyright (C) 1996 [email protected]).
[ 939.174533] BUG: kernel NULL pointer dereference, address: 0000000000000058
[ 939.174536] #PF: supervisor write access in kernel mode
[ 939.174538] #PF: error_code(0x0002) - not-present page
[ 939.174540] PGD 0 P4D 0
[ 939.174543] Oops: 0002 [#1] SMP PTI
[ 939.174546] CPU: 0 PID: 5031 Comm: modprobe Tainted: G O 5.3.0-51-generic #44~18.04.2-Ubuntu
[ 939.174548] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 939.174562] RIP: 0010:nfsd_fill_super+0x71/0x90 [nfsd]
[ 939.174565] Code: 85 c0 89 c3 74 09 89 d8 5b 41 5c 41 5d 5d c3 49 8b 7c 24 68 31 f6 48 c7 c2 70 24 9f c0 e8 97 fe ff ff 48 3d 00 f0 ff ff 77 0d <49> 89 45 58 89 d8 5b 41 5c 41 5d 5d c3 89 c3 eb cb 0f 1f 40 00 66
[ 939.174567] RSP: 0018:ffffaf12850f7aa8 EFLAGS: 00010287
[ 939.174569] RAX: ffff94269f29a600 RBX: 0000000000000000 RCX: 0000000000000002
[ 939.174570] RDX: 0000000000000000 RSI: 0000000000000100 RDI: ffff94269f30f820
[ 939.174572] RBP: ffffaf12850f7ac0 R08: ffff94269f29a620 R09: 0000000000000000
[ 939.174573] R10: 0000000000000000 R11: fefefefefefefeff R12: ffff942754da4800
[ 939.174575] R13: 0000000000000000 R14: ffffffffc09b94d0 R15: ffff94275b344480
[ 939.174577] FS: 00007f25508ed540(0000) GS:ffff94275ba00000(0000) knlGS:0000000000000000
[ 939.174579] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 939.174580] CR2: 0000000000000058 CR3: 00000000619be000 CR4: 00000000000406f0
[ 939.174586] Call Trace:
[ 939.174593] vfs_get_super+0x5b/0xe0
[ 939.174597] ? vfs_parse_fs_param+0xdc/0x1c0
[ 939.174608] nfsd_fs_get_tree+0x2c/0x30 [nfsd]
[ 939.174610] vfs_get_tree+0x2a/0x100
[ 939.174613] fc_mount+0x12/0x40
[ 939.174615] vfs_kern_mount.part.31+0x76/0x90
[ 939.174618] vfs_kern_mount+0x13/0x20
[ 939.174627] nfsd_init_net+0x101/0x140 [nfsd]
[ 939.174630] ops_init+0x44/0x120
[ 939.174633] register_pernet_operations+0xed/0x200
[ 939.174645] ? trace_event_define_fields_nfsd_stateid_class+0xb3/0xb3 [nfsd]
[ 939.174647] register_pernet_subsys+0x28/0x40
[ 939.174658] init_nfsd+0x22/0xcbc [nfsd]
[ 939.174661] do_one_initcall+0x4a/0x1fa
[ 939.174664] ? _cond_resched+0x19/0x40
[ 939.174667] ? kmem_cache_alloc_trace+0x15c/0x210
[ 939.174671] do_init_module+0x5f/0x227
[ 939.174674] load_module+0x1aa4/0x2140
[ 939.174678] __do_sys_finit_module+0xfc/0x120
[ 939.174681] ? __do_sys_finit_module+0xfc/0x120
[ 939.174684] __x64_sys_finit_module+0x1a/0x20
[ 939.174687] do_syscall_64+0x5a/0x130
[ 939.174690] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 939.174692] RIP: 0033:0x7f2550a3270d
[ 939.174694] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 53 f7 0c 00 f7 d8 64 89 01 48
[ 939.174696] RSP: 002b:00007ffd4a3d9738 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 939.174698] RAX: ffffffffffffffda RBX: 000055d5164584e0 RCX: 00007f2550a3270d
[ 939.174699] RDX: 0000000000000000 RSI: 000055d5146b7358 RDI: 0000000000000007
[ 939.174701] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000000
[ 939.174702] R10: 0000000000000007 R11: 0000000000000246 R12: 000055d5146b7358
[ 939.174704] R13: 0000000000000000 R14: 000055d5164547c0 R15: 000055d5164584e0
[ 939.174706] Modules linked in: nfsd(+) auth_rpcgss nfs_acl lockd grace veth xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c bpfilter br_netfilter bridge stp llc nls_utf8 isofs vboxsf(O) aufs overlay intel_rapl_msr snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer snd joydev soundcore vboxvideo intel_rapl_common drm_vram_helper ttm drm_kms_helper drm fb_sys_fops crct10dif_pclmul crc32_pclmul syscopyarea sysfillrect ghash_clmulni_intel sysimgblt aesni_intel aes_x86_64 crypto_simd cryptd glue_helper vboxguest(O) intel_rapl_perf input_leds mac_hid serio_raw binfmt_misc sch_fq_codel cuse sunrpc parport_pc ppdev lp parport ip_tables x_tables autofs4 hid_generic usbhid hid psmouse ahci libahci e1000 i2c_piix4 pata_acpi video
[ 939.174739] CR2: 0000000000000058
[ 939.174742] ---[ end trace 9fba6033f11f2b84 ]---
[ 939.174752] RIP: 0010:nfsd_fill_super+0x71/0x90 [nfsd]
[ 939.174754] Code: 85 c0 89 c3 74 09 89 d8 5b 41 5c 41 5d 5d c3 49 8b 7c 24 68 31 f6 48 c7 c2 70 24 9f c0 e8 97 fe ff ff 48 3d 00 f0 ff ff 77 0d <49> 89 45 58 89 d8 5b 41 5c 41 5d 5d c3 89 c3 eb cb 0f 1f 40 00 66
[ 939.174755] RSP: 0018:ffffaf12850f7aa8 EFLAGS: 00010287
[ 939.174757] RAX: ffff94269f29a600 RBX: 0000000000000000 RCX: 0000000000000002
[ 939.174759] RDX: 0000000000000000 RSI: 0000000000000100 RDI: ffff94269f30f820
[ 939.174760] RBP: ffffaf12850f7ac0 R08: ffff94269f29a620 R09: 0000000000000000
[ 939.174761] R10: 0000000000000000 R11: fefefefefefefeff R12: ffff942754da4800
[ 939.174763] R13: 0000000000000000 R14: ffffffffc09b94d0 R15: ffff94275b344480
[ 939.174765] FS: 00007f25508ed540(0000) GS:ffff94275ba00000(0000) knlGS:0000000000000000
[ 939.174766] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 939.174768] CR2: 0000000000000058 CR3: 00000000619be000 CR4: 00000000000406f0
Signed-off-by: Luo Xiaogang <[email protected]>
---
fs/nfsd/nfsctl.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index b68e96681522..87bb348a05ed 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1340,8 +1340,7 @@ void nfsd_client_rmdir(struct dentry *dentry)
static int nfsd_fill_super(struct super_block *sb, struct fs_context *fc)
{
- struct nfsd_net *nn = net_generic(current->nsproxy->net_ns,
- nfsd_net_id);
+ struct nfsd_net *nn = net_generic(fc->net_ns, nfsd_net_id);
struct dentry *dentry;
int ret;
@@ -1395,15 +1394,25 @@ static void nfsd_fs_free_fc(struct fs_context *fc)
put_net(fc->s_fs_info);
}
+static int nfsd_fs_parse_monolithic(struct fs_context *fc, void *data)
+{
+ put_net(fc->net_ns);
+ fc->net_ns = get_net(data);
+
+ put_user_ns(fc->user_ns);
+ fc->user_ns = get_user_ns(fc->net_ns->user_ns);
+
+ return 0;
+}
+
static const struct fs_context_operations nfsd_fs_context_ops = {
.free = nfsd_fs_free_fc,
.get_tree = nfsd_fs_get_tree,
+ .parse_monolithic = nfsd_fs_parse_monolithic,
};
static int nfsd_init_fs_context(struct fs_context *fc)
{
- put_user_ns(fc->user_ns);
- fc->user_ns = get_user_ns(fc->net_ns->user_ns);
fc->ops = &nfsd_fs_context_ops;
return 0;
}
@@ -1478,7 +1487,7 @@ static __net_init int nfsd_init_net(struct net *net)
init_waitqueue_head(&nn->ntf_wq);
seqlock_init(&nn->boot_lock);
- mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
+ mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", net);
if (IS_ERR(mnt)) {
retval = PTR_ERR(mnt);
goto out_mount_err;
--
2.17.1
On Mon, Jun 15, 2020 at 03:12:11PM +0800, Luo Xiaogang wrote:
> We load nfsd module in the docker container, kernel crash as following.
>
> The 'current->nsproxy->net_ns->gen->ptr[nfsd_net_id]' is overflow in the
> nfsd_init_net.
>
> We should use the net_ns which is being init in the nfsd_init_net,
> not the 'current->nsproxy->net_ns'.
Thanks! Actually, I think my problem was that net init and exit are
just the wrong place to be doing this--I moved them to nfsd start/stop
instead.
And then that exposed the fact that I had an inode leak.
Do the following two patches help?
--b.
From 16f954bd5c481596a63271a91963bf260e2f3f46 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <[email protected]>
Date: Tue, 23 Jun 2020 16:00:33 -0400
Subject: [PATCH 1/2] nfsd4: fix nfsdfs reference count loop
We don't drop the reference on the nfsdfs filesystem with
mntput(nn->nfsd_mnt) until nfsd_exit_net(), but that won't be called
until the nfsd module's unloaded, and we can't unload the module as long
as there's a reference on nfsdfs. So this prevents module unloading.
Signed-off-by: J. Bruce Fields <[email protected]>
---
fs/nfsd/nfs4state.c | 8 +++++++-
fs/nfsd/nfsctl.c | 22 ++++++++++++----------
fs/nfsd/nfsd.h | 3 +++
3 files changed, 22 insertions(+), 11 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index bb3d2c32664a..cce2510b2cca 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -7912,9 +7912,14 @@ nfs4_state_start_net(struct net *net)
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
int ret;
- ret = nfs4_state_create_net(net);
+ ret = get_nfsdfs(net);
if (ret)
return ret;
+ ret = nfs4_state_create_net(net);
+ if (ret) {
+ mntput(nn->nfsd_mnt);
+ return ret;
+ }
locks_start_grace(net, &nn->nfsd4_manager);
nfsd4_client_tracking_init(net);
if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0)
@@ -7984,6 +7989,7 @@ nfs4_state_shutdown_net(struct net *net)
nfsd4_client_tracking_exit(net);
nfs4_state_destroy_net(net);
+ mntput(nn->nfsd_mnt);
}
void
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index b68e96681522..cf98a81ca1ea 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1424,6 +1424,18 @@ static struct file_system_type nfsd_fs_type = {
};
MODULE_ALIAS_FS("nfsd");
+int get_nfsdfs(struct net *net)
+{
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+ struct vfsmount *mnt;
+
+ mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+ nn->nfsd_mnt = mnt;
+ return 0;
+}
+
#ifdef CONFIG_PROC_FS
static int create_proc_exports_entry(void)
{
@@ -1451,7 +1463,6 @@ unsigned int nfsd_net_id;
static __net_init int nfsd_init_net(struct net *net)
{
int retval;
- struct vfsmount *mnt;
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
retval = nfsd_export_init(net);
@@ -1478,16 +1489,8 @@ static __net_init int nfsd_init_net(struct net *net)
init_waitqueue_head(&nn->ntf_wq);
seqlock_init(&nn->boot_lock);
- mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
- if (IS_ERR(mnt)) {
- retval = PTR_ERR(mnt);
- goto out_mount_err;
- }
- nn->nfsd_mnt = mnt;
return 0;
-out_mount_err:
- nfsd_reply_cache_shutdown(nn);
out_drc_error:
nfsd_idmap_shutdown(net);
out_idmap_error:
@@ -1500,7 +1503,6 @@ static __net_exit void nfsd_exit_net(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
- mntput(nn->nfsd_mnt);
nfsd_reply_cache_shutdown(nn);
nfsd_idmap_shutdown(net);
nfsd_export_shutdown(net);
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 36cdd81b6688..57c832d1b30f 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -90,6 +90,8 @@ void nfsd_destroy(struct net *net);
bool i_am_nfsd(void);
+int get_nfsdfs(struct net *);
+
struct nfsdfs_client {
struct kref cl_ref;
void (*cl_release)(struct kref *kref);
@@ -100,6 +102,7 @@ struct dentry *nfsd_client_mkdir(struct nfsd_net *nn,
struct nfsdfs_client *ncl, u32 id, const struct tree_descr *);
void nfsd_client_rmdir(struct dentry *dentry);
+
#if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
#ifdef CONFIG_NFSD_V2_ACL
extern const struct svc_version nfsd_acl_version2;
--
2.26.2
From 51de3b460b39e862f7dcfd4d600e8de0afe73e29 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <[email protected]>
Date: Tue, 23 Jun 2020 21:01:19 -0400
Subject: [PATCH 2/2] nfsd: fix nfsdfs inode reference count leak
I don't understand this code well, but I'm seeing a warning about a
still-referenced inode on unmount, and every other similar filesystem
does a dput() here.
Signed-off-by: J. Bruce Fields <[email protected]>
---
fs/nfsd/nfsctl.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index cf98a81ca1ea..cd05732f8eaa 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1335,6 +1335,7 @@ void nfsd_client_rmdir(struct dentry *dentry)
WARN_ON_ONCE(ret);
fsnotify_rmdir(dir, dentry);
d_delete(dentry);
+ dput(dentry);
inode_unlock(dir);
}
--
2.26.2
Thanks for reply. Very well, the two patches you provided solved this problem.
On Fri, Jun 26, 2020 at 08:45:23PM +0800, Luo Xiaogang wrote:
> At 2020-06-24 09:29:01, "J. Bruce Fields" <[email protected]> wrote:
> >On Mon, Jun 15, 2020 at 03:12:11PM +0800, Luo Xiaogang wrote:
> >> We load nfsd module in the docker container, kernel crash as following.
> >>
> >> The 'current->nsproxy->net_ns->gen->ptr[nfsd_net_id]' is overflow in the
> >> nfsd_init_net.
> >>
> >> We should use the net_ns which is being init in the nfsd_init_net,
> >> not the 'current->nsproxy->net_ns'.
> >
> >Thanks! Actually, I think my problem was that net init and exit are
> >just the wrong place to be doing this--I moved them to nfsd start/stop
> >instead.
> >
> >And then that exposed the fact that I had an inode leak.
> >
> >Do the following two patches help?
>
> Just test it on Ubuntu 18.04 + Docker 19.03.6, and the docker image is ubuntu:18.04.
>
> Your patchset helps, here is my reported-and-tested-by, Thanks very much.
>
> Reported-and-Tested-by: Luo Xiaogang <[email protected]>
Thank you!
--b.
>
>
> >--b.
> >
> >From 16f954bd5c481596a63271a91963bf260e2f3f46 Mon Sep 17 00:00:00 2001
> >From: "J. Bruce Fields" <[email protected]>
> >Date: Tue, 23 Jun 2020 16:00:33 -0400
> >Subject: [PATCH 1/2] nfsd4: fix nfsdfs reference count loop
> >
> >We don't drop the reference on the nfsdfs filesystem with
> >mntput(nn->nfsd_mnt) until nfsd_exit_net(), but that won't be called
> >until the nfsd module's unloaded, and we can't unload the module as long
> >as there's a reference on nfsdfs. So this prevents module unloading.
> >
> >Signed-off-by: J. Bruce Fields <[email protected]>
> >---
> > fs/nfsd/nfs4state.c | 8 +++++++-
> > fs/nfsd/nfsctl.c | 22 ++++++++++++----------
> > fs/nfsd/nfsd.h | 3 +++
> > 3 files changed, 22 insertions(+), 11 deletions(-)
> >
> >diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >index bb3d2c32664a..cce2510b2cca 100644
> >--- a/fs/nfsd/nfs4state.c
> >+++ b/fs/nfsd/nfs4state.c
> >@@ -7912,9 +7912,14 @@ nfs4_state_start_net(struct net *net)
> > struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> > int ret;
> >
> >- ret = nfs4_state_create_net(net);
> >+ ret = get_nfsdfs(net);
> > if (ret)
> > return ret;
> >+ ret = nfs4_state_create_net(net);
> >+ if (ret) {
> >+ mntput(nn->nfsd_mnt);
> >+ return ret;
> >+ }
> > locks_start_grace(net, &nn->nfsd4_manager);
> > nfsd4_client_tracking_init(net);
> > if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0)
> >@@ -7984,6 +7989,7 @@ nfs4_state_shutdown_net(struct net *net)
> >
> > nfsd4_client_tracking_exit(net);
> > nfs4_state_destroy_net(net);
> >+ mntput(nn->nfsd_mnt);
> > }
> >
> > void
> >diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> >index b68e96681522..cf98a81ca1ea 100644
> >--- a/fs/nfsd/nfsctl.c
> >+++ b/fs/nfsd/nfsctl.c
> >@@ -1424,6 +1424,18 @@ static struct file_system_type nfsd_fs_type = {
> > };
> > MODULE_ALIAS_FS("nfsd");
> >
> >+int get_nfsdfs(struct net *net)
> >+{
> >+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> >+ struct vfsmount *mnt;
> >+
> >+ mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
> >+ if (IS_ERR(mnt))
> >+ return PTR_ERR(mnt);
> >+ nn->nfsd_mnt = mnt;
> >+ return 0;
> >+}
> >+
> > #ifdef CONFIG_PROC_FS
> > static int create_proc_exports_entry(void)
> > {
> >@@ -1451,7 +1463,6 @@ unsigned int nfsd_net_id;
> > static __net_init int nfsd_init_net(struct net *net)
> > {
> > int retval;
> >- struct vfsmount *mnt;
> > struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> >
> > retval = nfsd_export_init(net);
> >@@ -1478,16 +1489,8 @@ static __net_init int nfsd_init_net(struct net *net)
> > init_waitqueue_head(&nn->ntf_wq);
> > seqlock_init(&nn->boot_lock);
> >
> >- mnt = vfs_kern_mount(&nfsd_fs_type, SB_KERNMOUNT, "nfsd", NULL);
> >- if (IS_ERR(mnt)) {
> >- retval = PTR_ERR(mnt);
> >- goto out_mount_err;
> >- }
> >- nn->nfsd_mnt = mnt;
> > return 0;
> >
> >-out_mount_err:
> >- nfsd_reply_cache_shutdown(nn);
> > out_drc_error:
> > nfsd_idmap_shutdown(net);
> > out_idmap_error:
> >@@ -1500,7 +1503,6 @@ static __net_exit void nfsd_exit_net(struct net *net)
> > {
> > struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> >
> >- mntput(nn->nfsd_mnt);
> > nfsd_reply_cache_shutdown(nn);
> > nfsd_idmap_shutdown(net);
> > nfsd_export_shutdown(net);
> >diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> >index 36cdd81b6688..57c832d1b30f 100644
> >--- a/fs/nfsd/nfsd.h
> >+++ b/fs/nfsd/nfsd.h
> >@@ -90,6 +90,8 @@ void nfsd_destroy(struct net *net);
> >
> > bool i_am_nfsd(void);
> >
> >+int get_nfsdfs(struct net *);
> >+
> > struct nfsdfs_client {
> > struct kref cl_ref;
> > void (*cl_release)(struct kref *kref);
> >@@ -100,6 +102,7 @@ struct dentry *nfsd_client_mkdir(struct nfsd_net *nn,
> > struct nfsdfs_client *ncl, u32 id, const struct tree_descr *);
> > void nfsd_client_rmdir(struct dentry *dentry);
> >
> >+
> > #if defined(CONFIG_NFSD_V2_ACL) || defined(CONFIG_NFSD_V3_ACL)
> > #ifdef CONFIG_NFSD_V2_ACL
> > extern const struct svc_version nfsd_acl_version2;
> >--
> >2.26.2
> >
> >
> >From 51de3b460b39e862f7dcfd4d600e8de0afe73e29 Mon Sep 17 00:00:00 2001
> >From: "J. Bruce Fields" <[email protected]>
> >Date: Tue, 23 Jun 2020 21:01:19 -0400
> >Subject: [PATCH 2/2] nfsd: fix nfsdfs inode reference count leak
> >
> >I don't understand this code well, but I'm seeing a warning about a
> >still-referenced inode on unmount, and every other similar filesystem
> >does a dput() here.
> >
> >Signed-off-by: J. Bruce Fields <[email protected]>
> >---
> > fs/nfsd/nfsctl.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> >diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> >index cf98a81ca1ea..cd05732f8eaa 100644
> >--- a/fs/nfsd/nfsctl.c
> >+++ b/fs/nfsd/nfsctl.c
> >@@ -1335,6 +1335,7 @@ void nfsd_client_rmdir(struct dentry *dentry)
> > WARN_ON_ONCE(ret);
> > fsnotify_rmdir(dir, dentry);
> > d_delete(dentry);
> >+ dput(dentry);
> > inode_unlock(dir);
> > }
> >
> >--
> >2.26.2