Fix: ctf_user_integer should not trigger page fault

[deliverable/lttng-modules.git] / lttng-events.c

diff --git a/lttng-events.c b/lttng-events.c
index f0f5d0f80dbe340bf1e4663681ff621acd25f504..1f2863945a74f977fcc38b2635020064b80f84aa 100644 (file)
--- a/lttng-events.c
+++ b/lttng-events.c
@@ -36,21 +36,21 @@
 #include <linux/seq_file.h>
 #include <linux/file.h>
 #include <linux/anon_inodes.h>
-#include "wrapper/file.h"
+#include <wrapper/file.h>
 #include <linux/jhash.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
 
-#include "wrapper/uuid.h"
-#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
-#include "wrapper/random.h"
-#include "wrapper/tracepoint.h"
-#include "wrapper/list.h"
-#include "lttng-kernel-version.h"
-#include "lttng-events.h"
-#include "lttng-tracer.h"
-#include "lttng-abi-old.h"
-#include "wrapper/vzalloc.h"
+#include <wrapper/uuid.h>
+#include <wrapper/vmalloc.h>   /* for wrapper_vmalloc_sync_all() */
+#include <wrapper/random.h>
+#include <wrapper/tracepoint.h>
+#include <wrapper/list.h>
+#include <lttng-kernel-version.h>
+#include <lttng-events.h>
+#include <lttng-tracer.h>
+#include <lttng-abi-old.h>
+#include <wrapper/vzalloc.h>
 
 #define METADATA_CACHE_DEFAULT_SIZE 4096
 
@@ -2023,12 +2023,15 @@ int _lttng_event_header_declare(struct lttng_session *session)
  * taken at start of trace.
  * Yes, this is only an approximation. Yes, we can (and will) do better
  * in future versions.
+ * This function may return a negative offset. It may happen if the
+ * system sets the REALTIME clock to 0 after boot.
  */
 static
-uint64_t measure_clock_offset(void)
+int64_t measure_clock_offset(void)
 {
-       uint64_t offset, monotonic[2], realtime;
+       uint64_t monotonic_avg, monotonic[2], realtime;
        uint64_t tcf = trace_clock_freq();
+       int64_t offset;
        struct timespec rts = { 0, 0 };
        unsigned long flags;
 
@@ -2039,7 +2042,7 @@ uint64_t measure_clock_offset(void)
        monotonic[1] = trace_clock_read64();
        local_irq_restore(flags);
 
-       offset = (monotonic[0] + monotonic[1]) >> 1;
+       monotonic_avg = (monotonic[0] + monotonic[1]) >> 1;
        realtime = (uint64_t) rts.tv_sec * tcf;
        if (tcf == NSEC_PER_SEC) {
                realtime += rts.tv_nsec;
@@ -2049,7 +2052,7 @@ uint64_t measure_clock_offset(void)
                do_div(n, NSEC_PER_SEC);
                realtime += n;
        }
-       offset = realtime - offset;
+       offset = (int64_t) realtime - monotonic_avg;
        return offset;
 }
 
@@ -2161,11 +2164,11 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
                "       description = \"%s\";\n"
                "       freq = %llu; /* Frequency, in Hz */\n"
                "       /* clock value offset from Epoch is: offset * (1/freq) */\n"
-               "       offset = %llu;\n"
+               "       offset = %lld;\n"
                "};\n\n",
                trace_clock_description(),
                (unsigned long long) trace_clock_freq(),
-               (unsigned long long) measure_clock_offset()
+               (long long) measure_clock_offset()
                );
        if (ret)
                goto end;
@@ -2266,6 +2269,9 @@ static int __init lttng_events_init(void)
        if (ret)
                return ret;
        ret = wrapper_get_pfnblock_flags_mask_init();
+       if (ret)
+               return ret;
+       ret = wrapper_get_pageblock_flags_mask_init();
        if (ret)
                return ret;
        ret = lttng_context_init();