Fix: syscall tracing: missing trigger actions

[lttng-modules.git] / src / lttng-syscalls.c

diff --git a/src/lttng-syscalls.c b/src/lttng-syscalls.c
index bf1f2b732217397cf3e489bdb3e5f260f24dc361..d618bd33ae02474338608cc429dcb06dd461c004 100644 (file)
--- a/src/lttng-syscalls.c
+++ b/src/lttng-syscalls.c
@@ -130,6 +130,15 @@ struct lttng_syscall_filter {
        DECLARE_BITMAP(sc_exit, NR_syscalls);
        DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
        DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
+
+       /*
+        * Reference counters keeping track of number of events enabled
+        * for each bit.
+        */
+       u32 sc_entry_refcount_map[NR_syscalls];
+       u32 sc_exit_refcount_map[NR_syscalls];
+       u32 sc_compat_entry_refcount_map[NR_compat_syscalls];
+       u32 sc_compat_exit_refcount_map[NR_compat_syscalls];
 };
 
 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
@@ -973,6 +982,7 @@ int lttng_syscall_filter_enable(
 {
        const char *syscall_name;
        unsigned long *bitmap;
+       u32 *refcount_map;
        int syscall_nr;
 
        syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -995,9 +1005,11 @@ int lttng_syscall_filter_enable(
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_entry;
+                       refcount_map = filter->sc_entry_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_entry;
+                       refcount_map = filter->sc_compat_entry_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1007,9 +1019,11 @@ int lttng_syscall_filter_enable(
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_exit;
+                       refcount_map = filter->sc_exit_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_exit;
+                       refcount_map = filter->sc_compat_exit_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1018,9 +1032,10 @@ int lttng_syscall_filter_enable(
        default:
                return -EINVAL;
        }
-       if (test_bit(syscall_nr, bitmap))
-               return -EEXIST;
-       bitmap_set(bitmap, syscall_nr, 1);
+       if (refcount_map[syscall_nr] == U32_MAX)
+               return -EOVERFLOW;
+       if (refcount_map[syscall_nr]++ == 0)
+               bitmap_set(bitmap, syscall_nr, 1);
        return 0;
 }
 
@@ -1033,6 +1048,10 @@ int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
 
        WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
 
+       /* Skip unknown syscall */
+       if (syscall_id == -1U)
+               return 0;
+
        ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
                event->priv->desc->event_name, event->priv->u.syscall.abi,
                event->priv->u.syscall.entryexit);
@@ -1083,6 +1102,7 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 {
        const char *syscall_name;
        unsigned long *bitmap;
+       u32 *refcount_map;
        int syscall_nr;
 
        syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -1105,9 +1125,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_entry;
+                       refcount_map = filter->sc_entry_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_entry;
+                       refcount_map = filter->sc_compat_entry_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1117,9 +1139,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_exit;
+                       refcount_map = filter->sc_exit_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_exit;
+                       refcount_map = filter->sc_compat_exit_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1128,18 +1152,23 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
        default:
                return -EINVAL;
        }
-       if (!test_bit(syscall_nr, bitmap))
-               return -EEXIST;
-       bitmap_clear(bitmap, syscall_nr, 1);
-
+       if (refcount_map[syscall_nr] == 0)
+               return -ENOENT;
+       if (--refcount_map[syscall_nr] == 0)
+               bitmap_clear(bitmap, syscall_nr, 1);
        return 0;
 }
 
 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
 {
        struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
+       unsigned int syscall_id = event->priv->u.syscall.syscall_id;
        int ret;
 
+       /* Skip unknown syscall */
+       if (syscall_id == -1U)
+               return 0;
+
        ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
                event->priv->desc->event_name, event->priv->u.syscall.abi,
                event->priv->u.syscall.entryexit);