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Subject[PATCH] tools lib traceevent: Handle gcc __attribute__(()) in fields

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

When CONFIG_STURCTLEAK and gcc plugins are enabled, then some macros become
expanded and displayed as part of the format fields in the event format
files. For example, the __user macro expands to __attribute__((user)) and
the field buf for the syscall trace event sys_enter_write has it added:

# cat /sys/kernel/tracing/events/syscalls/sys_enter_write/format
name: sys_enter_write
ID: 680
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:unsigned int fd; offset:16; size:8; signed:0;
field:const char __attribute__((user)) * buf; offset:24; size:8; signed:0;
field:size_t count; offset:32; size:8; signed:0;

The "__attribute__((user))" breaks the parsing of the event. This needs to
also be handled.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205857
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---

Arnaldo,

Hold off on applying this, I want to hear back from the reporter (in
the bugzilla) to make sure this solves the issue for him.

-- Steve

tools/lib/traceevent/event-parse.c | 41 ++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index beaa8b8c08ff..ffba056772d5 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1477,6 +1477,47 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
/* read the rest of the type */
for (;;) {
type = read_token(&token);
+
+ /* On some configs, gcc __attribute((*)) may appear. */
+ if (type == TEP_EVENT_DELIM && strcmp(token, "(") == 0 &&
+ last_token && strcmp(last_token, "__attribute__") == 0) {
+ char *new_token;
+
+ breakpoint();
+ if (read_expected(TEP_EVENT_DELIM, "(") < 0) {
+ free(last_token);
+ goto fail;
+ }
+ free(token);
+ if (read_expect_type(TEP_EVENT_ITEM, &token) < 0) {
+ free(last_token);
+ goto fail;
+ }
+ new_token = realloc(last_token,
+ strlen(last_token) +
+ strlen(token) + 5);
+ if (!new_token) {
+ free(last_token);
+ goto fail;
+ }
+ last_token = new_token;
+ strcat(last_token, "((");
+ strcat(last_token, token);
+ strcat(last_token, "))");
+ free(token);
+ token = NULL;
+
+ if (read_expected(TEP_EVENT_DELIM, ")") < 0) {
+ free(last_token);
+ goto fail;
+ }
+ if (read_expected(TEP_EVENT_DELIM, ")") < 0) {
+ free(last_token);
+ goto fail;
+ }
+ continue;
+ }
+
if (type == TEP_EVENT_ITEM ||
(type == TEP_EVENT_OP && strcmp(token, "*") == 0) ||
/*
--
2.20.1
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