Show error if kernel tracer version don't match

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index d9e047fc3f5cdcc50a72ea68d0a7f29fa49b159b..86a1957cf400a2f8c6cd080ff42c28a864dda427 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -623,7 +623,8 @@ int kernel_validate_version(int tracer_fd)
        }
 
        /* Validate version */
-       if (version.version > KERN_MODULES_VERSION) {
+       if (version.version != KERN_MODULES_PRE_VERSION
+               && version.version != KERN_MODULES_VERSION) {
                goto error_version;
        }
 
@@ -638,3 +639,34 @@ error_version:
 error:
        return ret;
 }
+
+/*
+ * Kernel work-arounds called at the start of sessiond main().
+ */
+int init_kernel_workarounds(void)
+{
+       int ret;
+       FILE *fp;
+
+       /*
+        * boot_id needs to be read once before being used concurrently
+        * to deal with a Linux kernel race. A fix is proposed for
+        * upstream, but the work-around is needed for older kernels.
+        */
+       fp = fopen("/proc/sys/kernel/random/boot_id", "r");
+       if (!fp) {
+               goto end_boot_id;
+       }
+       while (!feof(fp)) {
+               char buf[37] = "";
+
+               ret = fread(buf, 1, sizeof(buf), fp);
+               if (ret < 0) {
+                       /* Ignore error, we don't really care */
+               }
+       }
+       fclose(fp);
+end_boot_id:
+
+       return 0;
+}