[Mesa-dev] [PATCH 3/3] gallium/hud: protect against and initialization race

[Steven Toth]

In the event that multiple threads attempt to install a graph
concurrently, protect the shared list.

Signed-off-by: Steven Toth <stoth at kernellabs.com>
---
 src/gallium/auxiliary/hud/hud_cpufreq.c      | 12 ++++++++++--
 src/gallium/auxiliary/hud/hud_diskstat.c     | 13 +++++++++++--
 src/gallium/auxiliary/hud/hud_nic.c          | 12 ++++++++++--
 src/gallium/auxiliary/hud/hud_sensors_temp.c | 12 ++++++++++--
 4 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/src/gallium/auxiliary/hud/hud_cpufreq.c b/src/gallium/auxiliary/hud/hud_cpufreq.c
index e66c3e4..19a6f08 100644
--- a/src/gallium/auxiliary/hud/hud_cpufreq.c
+++ b/src/gallium/auxiliary/hud/hud_cpufreq.c
@@ -36,6 +36,7 @@
 #include "hud/hud_private.h"
 #include "util/list.h"
 #include "os/os_time.h"
+#include "os/os_thread.h"
 #include "util/u_memory.h"
 #include <stdio.h>
 #include <unistd.h>
@@ -61,6 +62,7 @@ struct cpufreq_info
 
 static int gcpufreq_count = 0;
 static struct list_head gcpufreq_list;
+pipe_static_mutex(gcpufreq_mutex);
 
 static struct cpufreq_info *
 find_cfi_by_index(int cpu_index, int mode)
@@ -186,16 +188,21 @@ hud_get_num_cpufreq(bool displayhelp)
    int cpu_index;
 
    /* Return the number of CPU metrics we support. */
-   if (gcpufreq_count)
+   pipe_mutex_lock(gcpufreq_mutex);
+   if (gcpufreq_count) {
+      pipe_mutex_unlock(gcpufreq_mutex);
       return gcpufreq_count;
+   }
 
    /* Scan /sys/devices.../cpu, for every object type we support, create
     * and persist an object to represent its different metrics.
     */
    list_inithead(&gcpufreq_list);
    DIR *dir = opendir("/sys/devices/system/cpu");
-   if (!dir)
+   if (!dir) {
+      pipe_mutex_unlock(gcpufreq_mutex);
       return 0;
+   }
 
    while ((dp = readdir(dir)) != NULL) {
 
@@ -239,6 +246,7 @@ hud_get_num_cpufreq(bool displayhelp)
       }
    }
 
+   pipe_mutex_unlock(gcpufreq_mutex);
    return gcpufreq_count;
 }
 
diff --git a/src/gallium/auxiliary/hud/hud_diskstat.c b/src/gallium/auxiliary/hud/hud_diskstat.c
index d4306cd..af6e62d 100644
--- a/src/gallium/auxiliary/hud/hud_diskstat.c
+++ b/src/gallium/auxiliary/hud/hud_diskstat.c
@@ -35,6 +35,7 @@
 #include "hud/hud_private.h"
 #include "util/list.h"
 #include "os/os_time.h"
+#include "os/os_thread.h"
 #include "util/u_memory.h"
 #include <stdio.h>
 #include <unistd.h>
@@ -81,6 +82,7 @@ struct diskstat_info
  */
 static int gdiskstat_count = 0;
 static struct list_head gdiskstat_list;
+pipe_static_mutex(gdiskstat_mutex);
 
 static struct diskstat_info *
 find_dsi_by_name(const char *n, int mode)
@@ -244,16 +246,21 @@ hud_get_num_disks(bool displayhelp)
    char name[64];
 
    /* Return the number of block devices and partitions. */
-   if (gdiskstat_count)
+   pipe_mutex_lock(gdiskstat_mutex);
+   if (gdiskstat_count) {
+      pipe_mutex_unlock(gdiskstat_mutex);
       return gdiskstat_count;
+   }
 
    /* Scan /sys/block, for every object type we support, create and
     * persist an object to represent its different statistics.
     */
    list_inithead(&gdiskstat_list);
    DIR *dir = opendir("/sys/block/");
-   if (!dir)
+   if (!dir) {
+      pipe_mutex_unlock(gdiskstat_mutex);
       return 0;
+   }
 
    while ((dp = readdir(dir)) != NULL) {
 
@@ -278,6 +285,7 @@ hud_get_num_disks(bool displayhelp)
       struct dirent *dpart;
       DIR *pdir = opendir(basename);
       if (!pdir) {
+         pipe_mutex_unlock(gdiskstat_mutex);
          closedir(dir);
          return 0;
       }
@@ -312,6 +320,7 @@ hud_get_num_disks(bool displayhelp)
          puts(line);
       }
    }
+   pipe_mutex_unlock(gdiskstat_mutex);
 
    return gdiskstat_count;
 }
diff --git a/src/gallium/auxiliary/hud/hud_nic.c b/src/gallium/auxiliary/hud/hud_nic.c
index 2795c93..f9935de 100644
--- a/src/gallium/auxiliary/hud/hud_nic.c
+++ b/src/gallium/auxiliary/hud/hud_nic.c
@@ -35,6 +35,7 @@
 #include "hud/hud_private.h"
 #include "util/list.h"
 #include "os/os_time.h"
+#include "os/os_thread.h"
 #include "util/u_memory.h"
 #include <stdio.h>
 #include <unistd.h>
@@ -66,6 +67,7 @@ struct nic_info
  */
 static int gnic_count = 0;
 static struct list_head gnic_list;
+pipe_static_mutex(gnic_mutex);
 
 static struct nic_info *
 find_nic_by_name(const char *n, int mode)
@@ -329,16 +331,21 @@ hud_get_num_nics(bool displayhelp)
    char name[64];
 
    /* Return the number if network interfaces. */
-   if (gnic_count)
+   pipe_mutex_lock(gnic_mutex);
+   if (gnic_count) {
+      pipe_mutex_unlock(gnic_mutex);
       return gnic_count;
+   }
 
    /* Scan /sys/block, for every object type we support, create and
     * persist an object to represent its different statistics.
     */
    list_inithead(&gnic_list);
    DIR *dir = opendir("/sys/class/net/");
-   if (!dir)
+   if (!dir) {
+      pipe_mutex_unlock(gnic_mutex);
       return 0;
+   }
 
    while ((dp = readdir(dir)) != NULL) {
 
@@ -412,6 +419,7 @@ hud_get_num_nics(bool displayhelp)
 
    }
 
+   pipe_mutex_unlock(gnic_mutex);
    return gnic_count;
 }
 
diff --git a/src/gallium/auxiliary/hud/hud_sensors_temp.c b/src/gallium/auxiliary/hud/hud_sensors_temp.c
index 4a8a4fc..11b8a4c 100644
--- a/src/gallium/auxiliary/hud/hud_sensors_temp.c
+++ b/src/gallium/auxiliary/hud/hud_sensors_temp.c
@@ -32,6 +32,7 @@
 #include "hud/hud_private.h"
 #include "util/list.h"
 #include "os/os_time.h"
+#include "os/os_thread.h"
 #include "util/u_memory.h"
 #include <stdio.h>
 #include <unistd.h>
@@ -49,6 +50,7 @@
  */
 static int gsensors_temp_count = 0;
 static struct list_head gsensors_temp_list;
+pipe_static_mutex(gsensor_temp_mutex);
 
 struct sensors_temp_info
 {
@@ -322,12 +324,17 @@ int
 hud_get_num_sensors(bool displayhelp)
 {
    /* Return the number of sensors detected. */
-   if (gsensors_temp_count)
+   pipe_mutex_lock(gsensor_temp_mutex);
+   if (gsensors_temp_count) {
+      pipe_mutex_unlock(gsensor_temp_mutex);
       return gsensors_temp_count;
+   }
 
    int ret = sensors_init(NULL);
-   if (ret)
+   if (ret) {
+      pipe_mutex_unlock(gsensor_temp_mutex);
       return 0;
+   }
 
    list_inithead(&gsensors_temp_list);
 
@@ -361,6 +368,7 @@ hud_get_num_sensors(bool displayhelp)
       }
    }
 
+   pipe_mutex_unlock(gsensor_temp_mutex);
    return gsensors_temp_count;
 }
 
-- 
2.7.4