tracing: Remove "__attribute__()" from the type field of event format

With CONFIG_DEBUG_INFO_BTF=y and PAHOLE_HAS_BTF_TAG=y, `__user` is
converted to `__attribute__((btf_type_tag("user")))`. In this case,
some syscall events have it for __user data, like below;

/sys/kernel/tracing # cat events/syscalls/sys_enter_openat/format
name: sys_enter_openat
ID: 720
format:
        field:unsigned short common_type;       offset:0;       size:2; signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;

        field:int __syscall_nr; offset:8;       size:4; signed:1;
        field:int dfd;  offset:16;      size:8; signed:0;
        field:const char __attribute__((btf_type_tag("user"))) * filename;      offset:24;      size:8; signed:0;
        field:int flags;        offset:32;      size:8; signed:0;
        field:umode_t mode;     offset:40;      size:8; signed:0;

Then the trace event filter fails to set the string acceptable flag
(FILTER_PTR_STRING) to the field and rejects setting string filter;

 # echo 'filename.ustring ~ "*ftracetest-dir.wbx24v*"' \
    >> events/syscalls/sys_enter_openat/filter
 sh: write error: Invalid argument
 # cat error_log
 [  723.743637] event filter parse error: error: Expecting numeric field
   Command: filename.ustring ~ "*ftracetest-dir.wbx24v*"

Since this __attribute__ makes format parsing complicated and not
needed, remove the __attribute__(.*) from the type string.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/175376583493.1688759.12333973498014733551.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

1 files changed, 18 insertions, 10 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 06ab5b7a8711..945a8ecf2c62 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5930,17 +5930,27 @@ static inline void trace_insert_eval_map_file(struct module *mod,
 			      struct trace_eval_map **start, int len) { }
 #endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
 
-static void trace_insert_eval_map(struct module *mod,
-				  struct trace_eval_map **start, int len)
+static void
+trace_event_update_with_eval_map(struct module *mod,
+				 struct trace_eval_map **start,
+				 int len)
 {
 	struct trace_eval_map **map;
 
-	if (len <= 0)
-		return;
+	/* Always run sanitizer only if btf_type_tag attr exists. */
+	if (len <= 0) {
+		if (!(IS_ENABLED(CONFIG_DEBUG_INFO_BTF) &&
+		      IS_ENABLED(CONFIG_PAHOLE_HAS_BTF_TAG) &&
+		      __has_attribute(btf_type_tag)))
+			return;
+	}
 
 	map = start;
 
-	trace_event_eval_update(map, len);
+	trace_event_update_all(map, len);
+
+	if (len <= 0)
+		return;
 
 	trace_insert_eval_map_file(mod, start, len);
 }
@@ -10334,7 +10344,7 @@ static void __init eval_map_work_func(struct work_struct *work)
 	int len;
 
 	len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
-	trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
+	trace_event_update_with_eval_map(NULL, __start_ftrace_eval_maps, len);
 }
 
 static int __init trace_eval_init(void)
@@ -10387,9 +10397,6 @@ bool module_exists(const char *module)
 
 static void trace_module_add_evals(struct module *mod)
 {
-	if (!mod->num_trace_evals)
-		return;
-
 	/*
 	 * Modules with bad taint do not have events created, do
 	 * not bother with enums either.
@@ -10397,7 +10404,8 @@ static void trace_module_add_evals(struct module *mod)
 	if (trace_module_has_bad_taint(mod))
 		return;
 
-	trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
+	/* Even if no trace_evals, this need to sanitize field types. */
+	trace_event_update_with_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
 }
 
 #ifdef CONFIG_TRACE_EVAL_MAP_FILE