active-standby: add cmdline into /proc/net/

Add cmdline into /proc/net/{tcp,tcp6,udp,udp6} files.
Get process's cmdline from a sock's corresponding inode pointer,
 so that cmdline can't be used by Android active-standby app
to find the corresponding package name.

Resolve "BUG: scheduling while atomic" issue when
sk_get_waiting_task is being called.

Bug 1185001
Bug 1342554

Change-Id: Idc8651e4bb85b8a152dfade9689a719f7d72687d
(cherry picked from commit 5dcfe4f561bd8d1767e0938dfd7565b2b7718478)

Change-Id: I1673d56751a8a95b988b325b3857c8a5fe4c78ce
(cherry picked from commit 4516e7c330bb4c5da5020df0d2cc1cb5e9274d9f)
Signed-off-by: Chun Xu <chunx@nvidia.com>
Reviewed-on: http://git-master/r/336174
Reviewed-by: Harry Hong <hhong@nvidia.com>
Tested-by: Harry Hong <hhong@nvidia.com>

13 files changed, 258 insertions, 18 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 0863bab42c4d..205b31e10f6b 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -9,6 +9,8 @@
  *
  *  Davide Libenzi <davidel@xmailserver.org>
  *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ *
  */
 
 #include <linux/init.h>
@@ -893,7 +895,7 @@ static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd)
  * mechanism. It is called by the stored file descriptors when they
  * have events to report.
  */
-static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *key)
+int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *key)
 {
 	int pwake = 0;
 	unsigned long flags;
@@ -990,6 +992,7 @@ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
 
 	if (epi->nwait >= 0 && (pwq = kmem_cache_alloc(pwq_cache, GFP_KERNEL))) {
 		init_waitqueue_func_entry(&pwq->wait, ep_poll_callback);
+		pwq->wait.private = get_thread_process(current);
 		pwq->whead = whead;
 		pwq->base = epi;
 		add_wait_queue(whead, &pwq->wait);
@@ -1201,6 +1204,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 	spin_lock(&tfile->f_lock);
 	list_add_tail(&epi->fllink, &tfile->f_ep_links);
 	spin_unlock(&tfile->f_lock);
+	tfile->f_path.dentry->d_inode->i_private = get_thread_process(current);
 
 	/*
 	 * Add the current item to the RB tree. All RB tree operations are
@@ -1639,6 +1643,35 @@ static void clear_tfile_check_list(void)
 	INIT_LIST_HEAD(&tfile_check_list);
 }
 
+struct task_struct *get_epoll_file_task(struct file *file)
+{
+	struct list_head *lh;
+	struct epitem *epi = NULL;
+	struct eppoll_entry *pwq = NULL;
+	struct task_struct *task = NULL;
+	wait_queue_head_t *whead = NULL;
+	wait_queue_t *wq = NULL;
+
+	lh = &file->f_ep_links;
+	if (!list_empty(lh)) {
+		lh = lh->next;
+		epi = list_entry(lh, struct epitem, fllink);
+		lh = &epi->pwqlist;
+		if (!list_empty(lh)) {
+			lh = lh->next;
+			pwq = list_entry(lh, struct eppoll_entry, llink);
+			lh = &pwq->whead->task_list;
+			if (!list_empty(lh)) {
+				lh = lh->next;
+				wq = list_entry(lh, wait_queue_t, task_list);
+				task = wq->private;
+			}
+		}
+	}
+
+	return task;
+}
+
 /*
  * Open an eventpoll file descriptor.
  */
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c8cb15dcca08..68375ebe25c3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -45,6 +45,8 @@
  *
  *  Paul Mundt <paul.mundt@nokia.com>:
  *  Overall revision about smaps.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #include <asm/uaccess.h>
@@ -209,7 +211,7 @@ struct mm_struct *mm_for_maps(struct task_struct *task)
 	return mm_access(task, PTRACE_MODE_READ);
 }
 
-static int proc_pid_cmdline(struct task_struct *task, char * buffer)
+static int proc_pid_cmdline(struct task_struct *task, char *buffer)
 {
 	int res = 0;
 	unsigned int len;
diff --git a/fs/select.c b/fs/select.c
index 0baa0a351a1c..a010736dfe20 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -12,6 +12,8 @@
  *  24 January 2000
  *     Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 
  *     of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
+  *
+  * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #include <linux/kernel.h>
@@ -202,7 +204,7 @@ static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 	return default_wake_function(&dummy_wait, mode, sync, key);
 }
 
-static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
+int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 {
 	struct poll_table_entry *entry;
 
@@ -211,6 +213,7 @@ static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
 		return 0;
 	return __pollwake(wait, mode, sync, key);
 }
+EXPORT_SYMBOL(pollwake);
 
 /* Add a new entry */
 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 6f8be328770a..9378240bad9f 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -9,6 +9,8 @@
  *
  *  Davide Libenzi <davidel@xmailserver.org>
  *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ *
  */
 
 #ifndef _LINUX_EVENTPOLL_H
@@ -108,6 +110,9 @@ static inline void eventpoll_release(struct file *file)
 	eventpoll_release_file(file);
 }
 
+int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *key);
+struct task_struct *get_epoll_file_task(struct file *file);
+
 #else
 
 static inline void eventpoll_init_file(struct file *file) {}
diff --git a/include/linux/poll.h b/include/linux/poll.h
index 48fe8bc398d1..6769d98f2aeb 100644
--- a/include/linux/poll.h
+++ b/include/linux/poll.h
@@ -1,3 +1,7 @@
+/*
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ */
+
 #ifndef _LINUX_POLL_H
 #define _LINUX_POLL_H
 
@@ -96,6 +100,7 @@ struct poll_wqueues {
 
 extern void poll_initwait(struct poll_wqueues *pwq);
 extern void poll_freewait(struct poll_wqueues *pwq);
+extern int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key);
 extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 				 ktime_t *expires, unsigned long slack);
 extern long select_estimate_accuracy(struct timespec *tv);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 43ae5a574fdb..e5f98b9f0daa 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1,3 +1,7 @@
+/*
+ *  Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ */
+
 #ifndef _LINUX_SCHED_H
 #define _LINUX_SCHED_H
 
@@ -1682,6 +1686,15 @@ static inline struct pid *task_session(struct task_struct *task)
 	return task->group_leader->pids[PIDTYPE_SID].pid;
 }
 
+static inline struct task_struct *get_thread_process(struct task_struct *thread)
+{
+	struct task_struct *task = thread;
+	while (task->pid != task->tgid) {
+		task = task->group_leader;
+	}
+	return task;
+}
+
 struct pid_namespace;
 
 /*
diff --git a/include/net/sock.h b/include/net/sock.h
index f673ba5b6b1a..8083bbc5808c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -36,6 +36,8 @@
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 #ifndef _SOCK_H
 #define _SOCK_H
@@ -1488,6 +1490,8 @@ extern int compat_sock_common_setsockopt(struct socket *sock, int level,
 
 extern void sk_common_release(struct sock *sk);
 
+extern char *sk_get_waiting_task_cmdline(struct sock *sk, char *cmdline);
+
 /*
  *	Default socket callbacks and setup code
  */
diff --git a/net/core/sock.c b/net/core/sock.c
index 561eb57f590c..5dc8814db8db 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -87,6 +87,8 @@
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #include <linux/capability.h>
@@ -136,6 +138,8 @@
 #include <net/tcp.h>
 #endif
 
+#include <linux/eventpoll.h>
+
 static DEFINE_MUTEX(proto_list_mutex);
 static LIST_HEAD(proto_list);
 
@@ -2352,6 +2356,144 @@ void sk_common_release(struct sock *sk)
 }
 EXPORT_SYMBOL(sk_common_release);
 
+char *sk_get_waiting_task_cmdline(struct sock *sk, char *cmdline)
+{
+	bool softirq_enabled = false;
+	int res = 0;
+	unsigned int len;
+	char *program_name = cmdline;
+	struct task_struct *task = NULL;
+	struct mm_struct *mm = NULL;
+	static char *apk_path_prefix = "/data/data";
+	wait_queue_t *wq = NULL;
+	struct list_head *lh = NULL;
+	struct socket_wq *sk_wq = NULL;
+	wait_queue_func_t wait_func;
+	enum pid_type type;
+	struct pid *pid = NULL;
+	struct fown_struct *fown = NULL;
+	struct file *file;
+	int preempt_count;
+
+	*program_name = '\0';
+
+	if (!sk || !sk->sk_wq)
+		goto out;
+	lh = sk->sk_wq->wait.task_list.next;
+	if (!wq_has_sleeper(sk->sk_wq)) {
+		sk_wq = sk->sk_wq;
+		if (sk_wq->fasync_list && sk_wq->fasync_list->fa_file) {
+			fown = &sk_wq->fasync_list->fa_file->f_owner;
+			pid = fown->pid;
+			type = fown->pid_type;
+			do_each_pid_task(pid, type, task) {
+				if (task)
+					break;
+			} while_each_pid_task(pid, type, task);
+			printk(KERN_DEBUG "Async wakeup process:%p\n", task);
+		}
+	} else {
+		lh = sk->sk_wq->wait.task_list.next;
+		wq = list_entry(lh, wait_queue_t, task_list);
+
+		wait_func = wq->func;
+		printk(KERN_DEBUG "Wakeup function:%p\n", wait_func);
+		if (wait_func == pollwake)
+			task = ((struct poll_wqueues *)
+				(wq->private))->polling_task;
+		else if (wait_func == default_wake_function)
+			task = (struct task_struct *)(wq->private);
+		else if (wait_func == ep_poll_callback)
+			task = (struct task_struct *)(wq->private);
+		else if (wait_func == autoremove_wake_function)
+			task = (struct task_struct *)(wq->private);
+		else
+			printk(KERN_ERR "Unhandled wakeup:%p\n", wait_func);
+
+		if (task)
+			task = get_thread_process(task);
+	}
+
+#ifdef CONFIG_EPOLL
+	if (!task) {
+		file = sk->sk_socket->file;
+		if (file)
+			task = get_epoll_file_task(file);
+	}
+#endif
+
+	if (!task && sk && sk->sk_socket)
+		task = SOCK_INODE(sk->sk_socket)->i_private;
+
+	if (!task) {
+		printk(KERN_WARNING "Can't find a process for this sock.\n");
+		goto out;
+	}
+
+	mm = get_task_mm(task);
+	if (mm && mm->arg_end) {
+		len = mm->arg_end - mm->arg_start;
+
+		if (len > PAGE_SIZE)
+			len = PAGE_SIZE;
+
+		if (softirq_count()) {
+			softirq_enabled = true;
+			local_bh_enable();
+		}
+		if (preempt_count()) {
+			preempt_count = preempt_count();
+			preempt_count() = 0;
+		}
+
+		res = access_process_vm(task, mm->arg_start, cmdline, len, 0);
+
+		if (res > 0 && cmdline[res-1] != '\0' && len < PAGE_SIZE) {
+			len = strnlen(cmdline, res);
+			if (len < res) {
+				res = len;
+			} else {
+				len = mm->env_end - mm->env_start;
+				if (len > PAGE_SIZE - res)
+					len = PAGE_SIZE - res;
+				res += access_process_vm(task,
+					mm->env_start, cmdline+res, len, 0);
+				res = strnlen(cmdline, res);
+			}
+		}
+
+		if (preempt_count)
+			preempt_count() = preempt_count;
+		if (softirq_enabled)
+			local_bh_disable();
+
+		if (res > PAGE_SIZE)
+			cmdline[PAGE_SIZE-1] = '\0';
+
+		len = strlen(apk_path_prefix);
+		if (!strncmp(apk_path_prefix, program_name, len))
+			program_name += len;
+		else
+			program_name = strrchr(cmdline, '/');
+
+		if (program_name == NULL)
+			program_name = cmdline;
+		else
+			program_name++;
+	}
+
+	if (mm)
+		mmput(mm);
+
+	len = strlen(program_name);
+	snprintf(program_name + len, PAGE_SIZE-(program_name-cmdline)-len,
+		 " %d %s", task->pid, task->comm);
+out:
+	return program_name;
+}
+EXPORT_SYMBOL(sk_get_waiting_task_cmdline);
+
+
 #ifdef CONFIG_PROC_FS
 #define PROTO_INUSE_NR	64	/* should be enough for the first time */
 struct prot_inuse {
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ae03b7b75af6..46b8ce33154f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -48,6 +48,8 @@
  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
  *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
  *					a single port at the same time.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #define pr_fmt(fmt) "TCP: " fmt
@@ -2434,6 +2436,9 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
 	__u16 destp = ntohs(inet->inet_dport);
 	__u16 srcp = ntohs(inet->inet_sport);
 	int rx_queue;
+	unsigned long cmdline = __get_free_page(GFP_TEMPORARY);
+	if (cmdline == NULL)
+		return;
 
 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
 		timer_active	= 1;
@@ -2458,7 +2463,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
 		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
 
 	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
-			"%08X %5d %8d %lu %d %pK %lu %lu %u %u %d%n",
+		"%08X %5d %8d %lu %d %pK %lu %lu %u %u %d %s%n",
 		i, src, srcp, dest, destp, sk->sk_state,
 		tp->write_seq - tp->snd_una,
 		rx_queue,
@@ -2474,7 +2479,10 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
 		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
 		tp->snd_cwnd,
 		tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
+		sk_get_waiting_task_cmdline(sk, cmdline),
 		len);
+
+	free_page(cmdline);
 }
 
 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
@@ -2508,9 +2516,10 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
 
 	if (v == SEQ_START_TOKEN) {
 		seq_printf(seq, "%-*s\n", TMPSZ - 1,
-			   "  sl  local_address rem_address   st tx_queue "
-			   "rx_queue tr tm->when retrnsmt   uid  timeout "
-			   "inode");
+			"  sl  local_address rem_address   st tx_queue "
+			"rx_queue tr tm->when retrnsmt   uid  timeout "
+			"inode "
+			"cmdline");
 		goto out;
 	}
 	st = seq->private;
@@ -2527,7 +2536,7 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
 		get_timewait4_sock(v, seq, st->num, &len);
 		break;
 	}
-	seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
+	seq_printf(seq, "\n");
 out:
 	return 0;
 }
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 0b6136d578f6..c83b937e4914 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -75,6 +75,8 @@
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #define pr_fmt(fmt) "UDP: " fmt
@@ -2088,15 +2090,20 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
 	__be32 src  = inet->inet_rcv_saddr;
 	__u16 destp	  = ntohs(inet->inet_dport);
 	__u16 srcp	  = ntohs(inet->inet_sport);
+	unsigned long cmdline = __get_free_page(GFP_TEMPORARY);
+	if (cmdline == NULL)
+		return;
 
 	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
-		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
+		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d %s%n",
 		bucket, src, srcp, dest, destp, sp->sk_state,
 		sk_wmem_alloc_get(sp),
 		sk_rmem_alloc_get(sp),
 		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
 		atomic_read(&sp->sk_refcnt), sp,
-		atomic_read(&sp->sk_drops), len);
+		atomic_read(&sp->sk_drops),
+		sk_get_waiting_task_cmdline(sp, cmdline), len);
+	free_page(cmdline);
 }
 
 int udp4_seq_show(struct seq_file *seq, void *v)
@@ -2105,13 +2112,13 @@ int udp4_seq_show(struct seq_file *seq, void *v)
 		seq_printf(seq, "%-127s\n",
 			   "  sl  local_address rem_address   st tx_queue "
 			   "rx_queue tr tm->when retrnsmt   uid  timeout "
-			   "inode ref pointer drops");
+			   "inode ref pointer drops cmdline");
 	else {
 		struct udp_iter_state *state = seq->private;
 		int len;
 
 		udp4_format_sock(v, seq, state->bucket, &len);
-		seq_printf(seq, "%*s\n", 127 - len, "");
+		seq_printf(seq, "\n");
 	}
 	return 0;
 }
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7ee712167732..2624a8d6a842 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -21,6 +21,8 @@
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #include <linux/bottom_half.h>
@@ -1945,6 +1947,9 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
 	const struct tcp_sock *tp = tcp_sk(sp);
 	const struct inet_connection_sock *icsk = inet_csk(sp);
 	const struct ipv6_pinfo *np = inet6_sk(sp);
+	unsigned long cmdline = __get_free_page(GFP_TEMPORARY);
+	if (cmdline == NULL)
+		return;
 
 	dest  = &np->daddr;
 	src   = &np->rcv_saddr;
@@ -1967,7 +1972,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
 
 	seq_printf(seq,
 		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %lu %lu %u %u %d %s\n",
 		   i,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
@@ -1987,8 +1992,10 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
 		   jiffies_to_clock_t(icsk->icsk_ack.ato),
 		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
 		   tp->snd_cwnd,
-		   tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh
+		   tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
+		   sk_get_waiting_task_cmdline(sp, cmdline)
 		   );
+	free_page(cmdline);
 }
 
 static void get_timewait6_sock(struct seq_file *seq,
@@ -2030,7 +2037,7 @@ static int tcp6_seq_show(struct seq_file *seq, void *v)
 			 "local_address                         "
 			 "remote_address                        "
 			 "st tx_queue rx_queue tr tm->when retrnsmt"
-			 "   uid  timeout inode\n");
+			 "   uid  timeout inode cmdline\n");
 		goto out;
 	}
 	st = seq->private;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index f79bfdbc247f..29f6125592e1 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -19,6 +19,8 @@
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
+ *
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  */
 
 #include <linux/errno.h>
@@ -1397,6 +1399,9 @@ static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket
 	struct ipv6_pinfo *np = inet6_sk(sp);
 	const struct in6_addr *dest, *src;
 	__u16 destp, srcp;
+	unsigned long cmdline = __get_free_page(GFP_TEMPORARY);
+	if (cmdline == NULL)
+		return;
 
 	dest  = &np->daddr;
 	src   = &np->rcv_saddr;
@@ -1404,7 +1409,7 @@ static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket
 	srcp  = ntohs(inet->inet_sport);
 	seq_printf(seq,
 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
-		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d\n",
+		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d %s\n",
 		   bucket,
 		   src->s6_addr32[0], src->s6_addr32[1],
 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
@@ -1417,7 +1422,9 @@ static void udp6_sock_seq_show(struct seq_file *seq, struct sock *sp, int bucket
 		   sock_i_uid(sp), 0,
 		   sock_i_ino(sp),
 		   atomic_read(&sp->sk_refcnt), sp,
-		   atomic_read(&sp->sk_drops));
+		   atomic_read(&sp->sk_drops),
+		   sk_get_waiting_task_cmdline(sp, cmdline));
+	free_page(cmdline);
 }
 
 int udp6_seq_show(struct seq_file *seq, void *v)
@@ -1428,7 +1435,7 @@ int udp6_seq_show(struct seq_file *seq, void *v)
 			   "local_address                         "
 			   "remote_address                        "
 			   "st tx_queue rx_queue tr tm->when retrnsmt"
-			   "   uid  timeout inode ref pointer drops\n");
+			   "   uid  timeout inode ref pointer drops cmdline\n");
 	else
 		udp6_sock_seq_show(seq, v, ((struct udp_iter_state *)seq->private)->bucket);
 	return 0;
diff --git a/net/socket.c b/net/socket.c
index 47ce3ea44300..3eaf6884a421 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -868,6 +868,7 @@ static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,
 	msg->msg_iov = (struct iovec *)iov;
 	msg->msg_iovlen = nr_segs;
 	msg->msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;
+	SOCK_INODE(sock)->i_private = get_thread_process(current);
 
 	return __sock_recvmsg(iocb, sock, msg, size, msg->msg_flags);
 }
@@ -1103,6 +1104,7 @@ static unsigned int sock_poll(struct file *file, poll_table *wait)
 	 *      We can't return errors to poll, so it's either yes or no.
 	 */
 	sock = file->private_data;
+	SOCK_INODE(sock)->i_private = get_thread_process(current);
 	return sock->ops->poll(file, sock, wait);
 }
 
@@ -1349,6 +1351,7 @@ SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
 	retval = sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
 	if (retval < 0)
 		goto out_release;
+	SOCK_INODE(sock)->i_private = get_thread_process(current);
 
 out:
 	/* It may be already another descriptor 8) Not kernel problem. */