Thread (41 messages) 41 messages, 5 authors, 2017-08-14

[PATCH V15 09/11] ras: acpi / apei: generate trace event for unrecognized CPER section

From: rostedt@goodmis.org (Steven Rostedt)
Date: 2017-05-05 18:44:19
Also in: kvm, kvmarm, linux-acpi, linux-efi, lkml

Sorry for the late reply. Borislav pinged me to look at this.


On Tue, 18 Apr 2017 17:05:21 -0600
Tyler Baicar [off-list ref] wrote:


quoted hunk ↗ jump to hunk
diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
index 1791a12..5861b6f 100644
--- a/include/ras/ras_event.h
+++ b/include/ras/ras_event.h
@@ -162,6 +162,51 @@
 );
 
 /*
+ * Unknown Section Report
+ *
+ * This event is generated when hardware detected a hardware
+ * error event, which may be of non-standard section as defined
+ * in UEFI spec appendix "Common Platform Error Record", or may
+ * be of sections for which TRACE_EVENT is not defined.
+ *
+ */
+TRACE_EVENT(unknown_sec_event,
+
+	TP_PROTO(const uuid_le *sec_type,
+		 const uuid_le *fru_id,
+		 const char *fru_text,
+		 const u8 sev,
+		 const u8 *err,
+		 const u32 len),
+
+	TP_ARGS(sec_type, fru_id, fru_text, sev, err, len),
+
+	TP_STRUCT__entry(
+		__array(char, sec_type, 16)
+		__array(char, fru_id, 16)
+		__string(fru_text, fru_text)
+		__field(u8, sev)
+		__field(u32, len)
+		__dynamic_array(u8, buf, len)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->sec_type, sec_type, sizeof(uuid_le));
+		memcpy(__entry->fru_id, fru_id, sizeof(uuid_le));
My only concern here is that you are using sizeof(uuid_le) into an
array that is hardcoded as 16 bytes. I don't expect the size of uuid_le
to ever change, but if it does, you just created an exploit.

I would suggest having a macro about the size of uuid_le and use both
here and include/uapi/linux/uuid.h.

#define UUID_SIZE

typedef struct {
	__u8 b[UUID_SIZE];
} uuid_le;

And then we can just use UUID_SIZE safely here:

	__array(char, sec_type, UUID_SIZE)

[...]

	memcpy(__entry->sec_type, sec_type, UUID_SIZE));

Alternatively we could add in the C file that defines the tracepoints:

BUILD_BUG(sizeof(uuid_le) > 16);

But that's hacky.

+		__assign_str(fru_text, fru_text);
+		__entry->sev = sev;
+		__entry->len = len;
+		memcpy(__get_dynamic_array(buf), err, len);
+	),
+
+	TP_printk("severity: %d; sec type:%pU; FRU: %pU %s; data len:%d; raw data:%s",
+		  __entry->sev, __entry->sec_type,
Hmm, I wonder if %pU is defined in the libtraceevent library?

-- Steve
+		  __entry->fru_id, __get_str(fru_text),
+		  __entry->len,
+		  __print_hex(__get_dynamic_array(buf), __entry->len))
+);
+
+/*
  * PCIe AER Trace event
  *
  * These events are generated when hardware detects a corrected or
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