From da2c8fef130ec7197e2f91c7ed70a8c5bede4bea Mon Sep 17 00:00:00 2001
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Mon, 17 Jun 2024 16:26:26 +0200
Subject: [PATCH] NFSD: grab nfsd_mutex in nfsd_nl_rpc_status_get_dumpit()
Grab nfsd_mutex lock in nfsd_nl_rpc_status_get_dumpit routine and remove
nfsd_nl_rpc_status_get_start() and nfsd_nl_rpc_status_get_done(). This
patch fix the syzbot log reported below:
INFO: task syz-executor.1:17770 blocked for more than 143 seconds.
Not tainted 6.10.0-rc3-syzkaller-00022-gcea2a26553ac #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1 state:D stack:23800 pid:17770 tgid:17767 ppid:11381 flags:0x00000006
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5408 [inline]
__schedule+0x17e8/0x4a20 kernel/sched/core.c:6745
__schedule_loop kernel/sched/core.c:6822 [inline]
schedule+0x14b/0x320 kernel/sched/core.c:6837
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
__mutex_lock_common kernel/locking/mutex.c:684 [inline]
__mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752
nfsd_nl_listener_get_doit+0x115/0x5d0 fs/nfsd/nfsctl.c:2124
genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0xb16/0xec0 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x1e5/0x430 net/netlink/af_netlink.c:2564
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
netlink_unicast+0x7ec/0x980 net/netlink/af_netlink.c:1361
netlink_sendmsg+0x8db/0xcb0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x223/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2585
___sys_sendmsg net/socket.c:2639 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2668
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24ed27cea9
RSP: 002b:00007f24ee0080c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f24ed3b3f80 RCX: 00007f24ed27cea9
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000005
RBP: 00007f24ed2ebff4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
Fixes: 1bd773b4f0c9 ("nfsd: hold nfsd_mutex across entire netlink operation")
Fixes: bd9d6a3efa97 ("NFSD: add rpc_status netlink support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
Documentation/netlink/specs/nfsd.yaml | 2 --
fs/nfsd/netlink.c | 2 --
fs/nfsd/netlink.h | 3 --
fs/nfsd/nfsctl.c | 48 ++++++---------------------
4 files changed, 11 insertions(+), 44 deletions(-)
diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
index d212340971673..6bda7a4673018 100644
--- a/Documentation/netlink/specs/nfsd.yaml
+++ b/Documentation/netlink/specs/nfsd.yaml
@@ -123,8 +123,6 @@ operations:
doc: dump pending nfsd rpc
attribute-set: rpc-status
dump:
- pre: nfsd-nl-rpc-status-get-start
- post: nfsd-nl-rpc-status-get-done
reply:
attributes:
- xid
diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
index 62d2586d99025..529a75ecf22e8 100644
--- a/fs/nfsd/netlink.c
+++ b/fs/nfsd/netlink.c
@@ -44,9 +44,7 @@ static const struct nla_policy nfsd_listener_set_nl_policy[NFSD_A_SERVER_SOCK_AD
static const struct genl_split_ops nfsd_nl_ops[] = {
{
.cmd = NFSD_CMD_RPC_STATUS_GET,
- .start = nfsd_nl_rpc_status_get_start,
.dumpit = nfsd_nl_rpc_status_get_dumpit,
- .done = nfsd_nl_rpc_status_get_done,
.flags = GENL_CMD_CAP_DUMP,
},
{
diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h
index e3724637d64d5..2e132ef328f8d 100644
--- a/fs/nfsd/netlink.h
+++ b/fs/nfsd/netlink.h
@@ -15,9 +15,6 @@
extern const struct nla_policy nfsd_sock_nl_policy[NFSD_A_SOCK_TRANSPORT_NAME + 1];
extern const struct nla_policy nfsd_version_nl_policy[NFSD_A_VERSION_ENABLED + 1];
-int nfsd_nl_rpc_status_get_start(struct netlink_callback *cb);
-int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb);
-
int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 202140df8f82e..533b65057e18e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1460,28 +1460,6 @@ static int create_proc_exports_entry(void)
unsigned int nfsd_net_id;
-/**
- * nfsd_nl_rpc_status_get_start - Prepare rpc_status_get dumpit
- * @cb: netlink metadata and command arguments
- *
- * Return values:
- * %0: The rpc_status_get command may proceed
- * %-ENODEV: There is no NFSD running in this namespace
- */
-int nfsd_nl_rpc_status_get_start(struct netlink_callback *cb)
-{
- struct nfsd_net *nn = net_generic(sock_net(cb->skb->sk), nfsd_net_id);
- int ret = -ENODEV;
-
- mutex_lock(&nfsd_mutex);
- if (nn->nfsd_serv)
- ret = 0;
- else
- mutex_unlock(&nfsd_mutex);
-
- return ret;
-}
-
static int nfsd_genl_rpc_status_compose_msg(struct sk_buff *skb,
struct netlink_callback *cb,
struct nfsd_genl_rqstp *rqstp)
@@ -1558,8 +1536,16 @@ static int nfsd_genl_rpc_status_compose_msg(struct sk_buff *skb,
int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb)
{
- struct nfsd_net *nn = net_generic(sock_net(skb->sk), nfsd_net_id);
int i, ret, rqstp_index = 0;
+ struct nfsd_net *nn;
+
+ mutex_lock(&nfsd_mutex);
+
+ nn = net_generic(sock_net(skb->sk), nfsd_net_id);
+ if (!nn->nfsd_serv) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
rcu_read_lock();
@@ -1636,22 +1622,10 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
ret = skb->len;
out:
rcu_read_unlock();
-
- return ret;
-}
-
-/**
- * nfsd_nl_rpc_status_get_done - rpc_status_get dumpit post-processing
- * @cb: netlink metadata and command arguments
- *
- * Return values:
- * %0: Success
- */
-int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
-{
+out_unlock:
mutex_unlock(&nfsd_mutex);
- return 0;
+ return ret;
}
/**
--
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