proc_cpuview: release lock before returning

Fixes: #442
Cc: stable-4.0
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/proc_cpuview.c b/src/proc_cpuview.c
index c5bf9f98dc7ef045bd250c7f3004f35b7e6d4707..aaa3f531d4162cbd646859c8f0b10cf35c5be24c 100644 (file)
--- a/src/proc_cpuview.c
+++ b/src/proc_cpuview.c
@@ -315,7 +315,8 @@ out:
        return node;
 }
 
-static struct cg_proc_stat *find_or_create_proc_stat_node(struct cpuacct_usage *usage, int cpu_count, const char *cg)
+static struct cg_proc_stat *find_or_create_proc_stat_node(struct cpuacct_usage *usage,
+                                                         int cpu_count, const char *cg)
 {
        int hash = calc_hash(cg) % CPUVIEW_HASH_SIZE;
        struct cg_proc_stat_head *head = proc_stat_history[hash];
@@ -605,6 +606,7 @@ int cpuview_proc_stat(const char *cg, const char *cpuset,
        if (max_cpus > cpu_cnt || !max_cpus)
                max_cpus = cpu_cnt;
 
+       /* takes lock pthread_mutex_lock(&node->lock) */
        stat_node = find_or_create_proc_stat_node(cg_cpu_usage, nprocs, cg);
        if (!stat_node)
                return log_error(0, "Failed to find/create stat node for %s", cg);
@@ -760,8 +762,11 @@ int cpuview_proc_stat(const char *cg, const char *cpuset,
                     "cpu  %" PRIu64 " 0 %" PRIu64 " %" PRIu64 " 0 0 0 0 0 0\n",
                     user_sum, system_sum, idle_sum);
        lxcfs_v("cpu-all: %s\n", buf);
-       if (l < 0)
-               return log_error(0, "Failed to write cache");
+       if (l < 0) {
+               lxcfs_error("Failed to write cache");
+               total_len = 0;
+               goto out_pthread_mutex_unlock;
+       }
        if (l >= buf_size)
                return log_error(0, "Write to cache was truncated");
 
@@ -785,10 +790,16 @@ int cpuview_proc_stat(const char *cg, const char *cpuset,
                             stat_node->view[curcpu].system,
                             stat_node->view[curcpu].idle);
                lxcfs_v("cpu: %s\n", buf);
-               if (l < 0)
-                       return log_error(0, "Failed to write cache");
-               if (l >= buf_size)
-                       return log_error(0, "Write to cache was truncated");
+               if (l < 0) {
+                       lxcfs_error("Failed to write cache");
+                       total_len = 0;
+                       goto out_pthread_mutex_unlock;
+               }
+               if (l >= buf_size) {
+                       lxcfs_error("Write to cache was truncated");
+                       total_len = 0;
+                       goto out_pthread_mutex_unlock;
+               }
 
                buf += l;
                buf_size -= l;
@@ -797,10 +808,16 @@ int cpuview_proc_stat(const char *cg, const char *cpuset,
 
        /* Pass the rest of /proc/stat, start with the last line read */
        l = snprintf(buf, buf_size, "%s", line);
-       if (l < 0)
-               return log_error(0, "Failed to write cache");
-       if (l >= buf_size)
-               return log_error(0, "Write to cache was truncated");
+       if (l < 0) {
+               lxcfs_error("Failed to write cache");
+               total_len = 0;
+               goto out_pthread_mutex_unlock;
+       }
+       if (l >= buf_size) {
+               lxcfs_error("Write to cache was truncated");
+               total_len = 0;
+               goto out_pthread_mutex_unlock;
+       }
 
        buf += l;
        buf_size -= l;
@@ -809,16 +826,23 @@ int cpuview_proc_stat(const char *cg, const char *cpuset,
        /* Pass the rest of the host's /proc/stat */
        while (getline(&line, &linelen, f) != -1) {
                l = snprintf(buf, buf_size, "%s", line);
-               if (l < 0)
-                       return log_error(0, "Failed to write cache");
-               if (l >= buf_size)
-                       return log_error(0, "Write to cache was truncated");
+               if (l < 0) {
+                       lxcfs_error("Failed to write cache");
+                       total_len = 0;
+                       goto out_pthread_mutex_unlock;
+               }
+               if (l >= buf_size) {
+                       lxcfs_error("Write to cache was truncated");
+                       total_len = 0;
+                       goto out_pthread_mutex_unlock;
+               }
 
                buf += l;
                buf_size -= l;
                total_len += l;
        }
 
+out_pthread_mutex_unlock:
        if (stat_node)
                pthread_mutex_unlock(&stat_node->lock);