[lxc-devel] [lxc/master] cgroup: bugfixes

brauner on Github lxc-bot at linuxcontainers.org
Sun Feb 10 09:58:59 UTC 2019


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From f2668eea509deccb77a90dac8a12f43bfcb6178f Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Sun, 10 Feb 2019 10:51:43 +0100
Subject: [PATCH 1/3] cgfsng: coding style for cgfsng_monitor_create()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/lxc/cgroups/cgfsng.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index 2049363b3..d03fcf390 100644
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1329,7 +1329,7 @@ static void remove_path_for_hierarchy(struct hierarchy *h, char *cgname, bool mo
 }
 
 __cgfsng_ops static inline bool cgfsng_monitor_create(struct cgroup_ops *ops,
-							struct lxc_handler *handler)
+						      struct lxc_handler *handler)
 {
 	__do_free char *monitor_cgroup = NULL;
 	char *offset, *tmp;
@@ -1367,10 +1367,14 @@ __cgfsng_ops static inline bool cgfsng_monitor_create(struct cgroup_ops *ops,
 		}
 
 		for (i = 0; ops->hierarchies[i]; i++) {
-			if (!monitor_create_path_for_hierarchy(ops->hierarchies[i], monitor_cgroup)) {
-				ERROR("Failed to create cgroup \"%s\"", ops->hierarchies[i]->monitor_full_path);
+			if (!monitor_create_path_for_hierarchy(ops->hierarchies[i],
+							       monitor_cgroup)) {
+				ERROR("Failed to create cgroup \"%s\"",
+				      ops->hierarchies[i]->monitor_full_path);
 				for (int j = 0; j < i; j++)
-					remove_path_for_hierarchy(ops->hierarchies[j], monitor_cgroup, true);
+					remove_path_for_hierarchy(ops->hierarchies[j],
+								  monitor_cgroup,
+								  true);
 
 				idx++;
 				break;

From d99d5c935a9ee2eb66ba9e55e85bd707d4c1647b Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Sun, 10 Feb 2019 10:52:45 +0100
Subject: [PATCH 2/3] cgfsng: coding style for cgfsng_payload_create()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/lxc/cgroups/cgfsng.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index d03fcf390..76c7647b5 100644
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1431,10 +1431,14 @@ __cgfsng_ops static inline bool cgfsng_payload_create(struct cgroup_ops *ops,
 			return false;
 
 		for (i = 0; ops->hierarchies[i]; i++) {
-			if (!container_create_path_for_hierarchy(ops->hierarchies[i], container_cgroup)) {
-				ERROR("Failed to create cgroup \"%s\"", ops->hierarchies[i]->container_full_path);
+			if (!container_create_path_for_hierarchy(ops->hierarchies[i],
+								 container_cgroup)) {
+				ERROR("Failed to create cgroup \"%s\"",
+				      ops->hierarchies[i]->container_full_path);
 				for (int j = 0; j < i; j++)
-					remove_path_for_hierarchy(ops->hierarchies[j], container_cgroup, false);
+					remove_path_for_hierarchy(ops->hierarchies[j],
+								  container_cgroup,
+								  false);
 				idx++;
 				break;
 			}

From c74da4abd20ede6a30c358dc275ba43b1d12e8d5 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Sun, 10 Feb 2019 10:53:06 +0100
Subject: [PATCH 3/3] cgfsng: fix cgroup creation
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When cgroup creation failed we reset container_cgroup to NULL to avoid
issues with __cleanup__. Fix that logic:
- add steal_ptr() based on take_ptr()
- move stealing the pointer out of the loop

lxc ctImport 20190210050705.858 DEBUG    network - network.c:instantiate_veth:202 - Instantiated veth "vethGQMH7I/vethSPXNL3", index is "272"
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:mkdir_eexist_on_last:1262 - File exists - Failed to create directory "/sys/fs/cgroup/unified//lxc.payload/ctImport-0"
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:container_create_path_for_hierarchy:1302 - Failed to create cgroup "/sys/fs/cgroup/unified//lxc.payload/ctImport-0"
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:cgfsng_payload_create:1431 - Failed to create cgroup "/sys/fs/cgroup/unified//lxc.payload/ctImport-0"
lxc ctImport 20190210050705.858 INFO     cgfsng - cgroups/cgfsng.c:cgfsng_payload_create:1441 - The container uses "lxc.payload/ctImport-0" as cgroup
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:mkdir_eexist_on_last:1262 - File exists - Failed to create directory "/sys/fs/cgroup/unified/"
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:container_create_path_for_hierarchy:1302 - Failed to create cgroup "/sys/fs/cgroup/unified/"
lxc ctImport 20190210050705.858 ERROR    cgfsng - cgroups/cgfsng.c:cgfsng_payload_create:1431 - Failed to create cgroup "/sys/fs/cgroup/unified/"
lxc ctImport 20190210050705.858 INFO     cgfsng - cgroups/cgfsng.c:cgfsng_payload_create:1441 - The container uses "(null)" as cgroup

Fixes: d97919abf22 ("cgroups: partially switch to cleanup macros")
Reported-by: Stéphane Graber <stgraber at ubuntu.com>
Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/lxc/cgroups/cgfsng.c | 15 +++++++--------
 src/lxc/macro.h          |  7 +++++++
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/lxc/cgroups/cgfsng.c b/src/lxc/cgroups/cgfsng.c
index 76c7647b5..971c6a523 100644
--- a/src/lxc/cgroups/cgfsng.c
+++ b/src/lxc/cgroups/cgfsng.c
@@ -1426,9 +1426,11 @@ __cgfsng_ops static inline bool cgfsng_payload_create(struct cgroup_ops *ops,
 	offset = container_cgroup + len - 5;
 
 	do {
-		int ret = snprintf(offset, 5, "-%d", idx);
-		if (ret < 0 || (size_t)ret >= 5)
-			return false;
+		if (idx) {
+			int ret = snprintf(offset, 5, "-%d", idx);
+			if (ret < 0 || (size_t)ret >= 5)
+				return false;
+		}
 
 		for (i = 0; ops->hierarchies[i]; i++) {
 			if (!container_create_path_for_hierarchy(ops->hierarchies[i],
@@ -1443,16 +1445,13 @@ __cgfsng_ops static inline bool cgfsng_payload_create(struct cgroup_ops *ops,
 				break;
 			}
 		}
-
-		ops->container_cgroup = container_cgroup;
-		container_cgroup = NULL;
-		INFO("The container uses \"%s\" as cgroup", ops->container_cgroup);
 	} while (ops->hierarchies[i] && idx > 0 && idx < 1000);
 
 	if (idx == 1000)
 		return false;
 
-	INFO("The container process uses \"%s\" as cgroup", ops->container_cgroup);
+	INFO("The container process uses \"%s\" as cgroup", container_cgroup);
+	ops->container_cgroup = steal_ptr(container_cgroup);
 	return true;
 }
 
diff --git a/src/lxc/macro.h b/src/lxc/macro.h
index 30aa2a5a5..14e12670e 100644
--- a/src/lxc/macro.h
+++ b/src/lxc/macro.h
@@ -392,4 +392,11 @@ enum {
 /* Maximum number of bytes sendfile() is able to send in one go. */
 #define LXC_SENDFILE_MAX 0x7ffff000
 
+#define steal_ptr(ptr)                     \
+	({                                 \
+		typeof(ptr) _ptr_ = (ptr); \
+		(ptr) = NULL;              \
+		_ptr_;                     \
+	})
+
 #endif /* __LXC_MACRO_H */


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