Merge tag 'trace-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...

Pull tracing fixes from Steven Rostedt:

 - Do not allow histogram values to have modifies. They can cause a NULL
   pointer dereference if they do.

 - Warn if hist_field_name() is passed a NULL. Prevent the NULL pointer
   dereference mentioned above.

 - Fix invalid address look up race in lookup_rec()

 - Define ftrace_stub_graph conditionally to prevent linker errors

 - Always check if RCU is watching at all tracepoint locations

* tag 'trace-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Make tracepoint lockdep check actually test something
  ftrace,kcfi: Define ftrace_stub_graph conditionally
  ftrace: Fix invalid address access in lookup_rec() when index is 0
  tracing: Check field value in hist_field_name()
  tracing: Do not let histogram values have some modifiers

diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index 1265ad519249c027cae82d8941d394b8dbc50795..fb4f1e01b64a28af7b85ff26fa8edac39ce67bd6 100644 (file)
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -136,10 +136,12 @@ SYM_TYPED_FUNC_START(ftrace_stub)
        RET
 SYM_FUNC_END(ftrace_stub)
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 SYM_TYPED_FUNC_START(ftrace_stub_graph)
        CALL_DEPTH_ACCOUNT
        RET
 SYM_FUNC_END(ftrace_stub_graph)
+#endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index e299f29375bb7f1e55789adca45b45e31bebde84..6811e43c1b5c2afed0bad0a2e7469e8573916eb9 100644 (file)
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -242,12 +242,11 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
  * not add unwanted padding between the beginning of the section and the
  * structure. Force alignment to the same alignment as the section start.
  *
- * When lockdep is enabled, we make sure to always do the RCU portions of
- * the tracepoint code, regardless of whether tracing is on. However,
- * don't check if the condition is false, due to interaction with idle
- * instrumentation. This lets us find RCU issues triggered with tracepoints
- * even when this tracepoint is off. This code has no purpose other than
- * poking RCU a bit.
+ * When lockdep is enabled, we make sure to always test if RCU is
+ * "watching" regardless if the tracepoint is enabled or not. Tracepoints
+ * require RCU to be active, and it should always warn at the tracepoint
+ * site if it is not watching, as it will need to be active when the
+ * tracepoint is enabled.
  */
 #define __DECLARE_TRACE(name, proto, args, cond, data_proto)           \
        extern int __traceiter_##name(data_proto);                      \
@@ -260,9 +259,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
                                TP_ARGS(args),                          \
                                TP_CONDITION(cond), 0);                 \
                if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) {             \
-                       rcu_read_lock_sched_notrace();                  \
-                       rcu_dereference_sched(__tracepoint_##name.funcs);\
-                       rcu_read_unlock_sched_notrace();                \
+                       WARN_ON_ONCE(!rcu_is_watching());               \
                }                                                       \
        }                                                               \
        __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args),          \

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 29baa97d0d534284237a4376dda1d88aca6f7c06..9b2803c7a18f8e54fe99b02bd22794d0e52f58d8 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1564,7 +1564,8 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
        key.flags = end;        /* overload flags, as it is unsigned long */
 
        for (pg = ftrace_pages_start; pg; pg = pg->next) {
-               if (end < pg->records[0].ip ||
+               if (pg->index == 0 ||
+                   end < pg->records[0].ip ||
                    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
                        continue;
                rec = bsearch(&key, pg->records, pg->index,

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 89877a18f93307fce29789166b68a60d9a7f0c1e..486cca3c2b75450f23f8b680045421cf234d232f 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1331,6 +1331,9 @@ static const char *hist_field_name(struct hist_field *field,
 {
        const char *field_name = "";
 
+       if (WARN_ON_ONCE(!field))
+               return field_name;
+
        if (level > 1)
                return field_name;
 
@@ -4235,6 +4238,15 @@ static int __create_val_field(struct hist_trigger_data *hist_data,
                goto out;
        }
 
+       /* Some types cannot be a value */
+       if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT |
+                                HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 |
+                                HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET |
+                                HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE)) {
+               hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str));
+               ret = -EINVAL;
+       }
+
        hist_data->fields[val_idx] = hist_field;
 
        ++hist_data->n_vals;