[dpdk-stable] patch 'vhost: fix race condition when adding fd in the fdset' has been queued to LTS release 17.11.6

[Yongseok Koh <yskoh@mellanox.com>]

Hi,

FYI, your patch has been queued to LTS release 17.11.6

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objection by 03/13/19. So please
shout if anyone has objection.

Also note that after the patch there's a diff of the upstream commit vs the patch applied
to the branch. If the code is different (ie: not only metadata diffs), due for example to
a change in context or macro names, please double check it.

Thanks.

Yongseok

---
>From c9e1dc6a57b23f85beee8db9410e2951129629c4 Mon Sep 17 00:00:00 2001
From: Matthias Gatto <matthias.gatto@outscale.com>
Date: Thu, 6 Dec 2018 16:00:07 +0000
Subject: [PATCH] vhost: fix race condition when adding fd in the fdset

[ upstream commit 276d63505be94bb8d5fdf754af0105707ea433c1 ]

fdset_add can call fdset_shrink_nolock which call fdset_move
concurrently to poll that is call in fdset_event_dispatch.

This patch add a mutex to protect poll from been call at the same time
fdset_add call fdset_shrink_nolock.

Fixes: 1b815b89599c ("vhost: try to shrink pfdset when fdset_add fails")

Signed-off-by: Matthias Gatto <matthias.gatto@outscale.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/fd_man.c | 4 ++++
 lib/librte_vhost/fd_man.h | 1 +
 lib/librte_vhost/socket.c | 1 +
 3 files changed, 6 insertions(+)

diff --git a/lib/librte_vhost/fd_man.c b/lib/librte_vhost/fd_man.c
index 173ec75c8..0ab67c501 100644
--- a/lib/librte_vhost/fd_man.c
+++ b/lib/librte_vhost/fd_man.c
@@ -155,7 +155,9 @@ fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat)
 	pthread_mutex_lock(&pfdset->fd_mutex);
 	i = pfdset->num < MAX_FDS ? pfdset->num++ : -1;
 	if (i == -1) {
+		pthread_mutex_lock(&pfdset->fd_pooling_mutex);
 		fdset_shrink_nolock(pfdset);
+		pthread_mutex_unlock(&pfdset->fd_pooling_mutex);
 		i = pfdset->num < MAX_FDS ? pfdset->num++ : -1;
 		if (i == -1) {
 			pthread_mutex_unlock(&pfdset->fd_mutex);
@@ -272,7 +274,9 @@ fdset_event_dispatch(void *arg)
 		numfds = pfdset->num;
 		pthread_mutex_unlock(&pfdset->fd_mutex);
 
+		pthread_mutex_lock(&pfdset->fd_pooling_mutex);
 		val = poll(pfdset->rwfds, numfds, 1000 /* millisecs */);
+		pthread_mutex_unlock(&pfdset->fd_pooling_mutex);
 		if (val < 0)
 			continue;
 
diff --git a/lib/librte_vhost/fd_man.h b/lib/librte_vhost/fd_man.h
index c00883882..01882de6c 100644
--- a/lib/librte_vhost/fd_man.h
+++ b/lib/librte_vhost/fd_man.h
@@ -53,6 +53,7 @@ struct fdset {
 	struct pollfd rwfds[MAX_FDS];
 	struct fdentry fd[MAX_FDS];
 	pthread_mutex_t fd_mutex;
+	pthread_mutex_t fd_pooling_mutex;
 	int num;	/* current fd number of this fdset */
 };
 
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index f816601bb..a3fd3dc23 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -110,6 +110,7 @@ static struct vhost_user vhost_user = {
 	.fdset = {
 		.fd = { [0 ... MAX_FDS - 1] = {-1, NULL, NULL, NULL, 0} },
 		.fd_mutex = PTHREAD_MUTEX_INITIALIZER,
+		.fd_pooling_mutex = PTHREAD_MUTEX_INITIALIZER,
 		.num = 0
 	},
 	.vsocket_cnt = 0,
-- 
2.11.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-03-08 09:46:41.171914945 -0800
+++ 0016-vhost-fix-race-condition-when-adding-fd-in-the-fdset.patch	2019-03-08 09:46:40.036402000 -0800
@@ -1,8 +1,10 @@
-From 276d63505be94bb8d5fdf754af0105707ea433c1 Mon Sep 17 00:00:00 2001
+From c9e1dc6a57b23f85beee8db9410e2951129629c4 Mon Sep 17 00:00:00 2001
 From: Matthias Gatto <matthias.gatto@outscale.com>
 Date: Thu, 6 Dec 2018 16:00:07 +0000
 Subject: [PATCH] vhost: fix race condition when adding fd in the fdset
 
+[ upstream commit 276d63505be94bb8d5fdf754af0105707ea433c1 ]
+
 fdset_add can call fdset_shrink_nolock which call fdset_move
 concurrently to poll that is call in fdset_event_dispatch.
 
@@ -10,7 +12,6 @@
 fdset_add call fdset_shrink_nolock.
 
 Fixes: 1b815b89599c ("vhost: try to shrink pfdset when fdset_add fails")
-Cc: stable@dpdk.org
 
 Signed-off-by: Matthias Gatto <matthias.gatto@outscale.com>
 Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
@@ -21,10 +22,10 @@
  3 files changed, 6 insertions(+)
 
 diff --git a/lib/librte_vhost/fd_man.c b/lib/librte_vhost/fd_man.c
-index 38347ab1d..55d4856f9 100644
+index 173ec75c8..0ab67c501 100644
 --- a/lib/librte_vhost/fd_man.c
 +++ b/lib/librte_vhost/fd_man.c
-@@ -129,7 +129,9 @@ fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat)
+@@ -155,7 +155,9 @@ fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, void *dat)
  	pthread_mutex_lock(&pfdset->fd_mutex);
  	i = pfdset->num < MAX_FDS ? pfdset->num++ : -1;
  	if (i == -1) {
@@ -34,7 +35,7 @@
  		i = pfdset->num < MAX_FDS ? pfdset->num++ : -1;
  		if (i == -1) {
  			pthread_mutex_unlock(&pfdset->fd_mutex);
-@@ -246,7 +248,9 @@ fdset_event_dispatch(void *arg)
+@@ -272,7 +274,9 @@ fdset_event_dispatch(void *arg)
  		numfds = pfdset->num;
  		pthread_mutex_unlock(&pfdset->fd_mutex);
  
@@ -45,22 +46,22 @@
  			continue;
  
 diff --git a/lib/librte_vhost/fd_man.h b/lib/librte_vhost/fd_man.h
-index 3331bcd97..3ab5cfdd6 100644
+index c00883882..01882de6c 100644
 --- a/lib/librte_vhost/fd_man.h
 +++ b/lib/librte_vhost/fd_man.h
-@@ -24,6 +24,7 @@ struct fdset {
+@@ -53,6 +53,7 @@ struct fdset {
  	struct pollfd rwfds[MAX_FDS];
  	struct fdentry fd[MAX_FDS];
  	pthread_mutex_t fd_mutex;
 +	pthread_mutex_t fd_pooling_mutex;
  	int num;	/* current fd number of this fdset */
+ };
  
- 	union pipefds {
 diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
-index 01b60ff9e..9cf34ad17 100644
+index f816601bb..a3fd3dc23 100644
 --- a/lib/librte_vhost/socket.c
 +++ b/lib/librte_vhost/socket.c
-@@ -90,6 +90,7 @@ static struct vhost_user vhost_user = {
+@@ -110,6 +110,7 @@ static struct vhost_user vhost_user = {
  	.fdset = {
  		.fd = { [0 ... MAX_FDS - 1] = {-1, NULL, NULL, NULL, 0} },
  		.fd_mutex = PTHREAD_MUTEX_INITIALIZER,