Merge tag 'trace-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This is mostly clean ups and small fixes.  Some of the more visible
  changes are:

   - The function pid code uses the event pid filtering logic
   - [ku]probe events have access to current->comm
   - trace_printk now has sample code
   - PCI devices now trace physical addresses
   - stack tracing has less unnessary functions traced"

* tag 'trace-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  printk, tracing: Avoiding unneeded blank lines
  tracing: Use __get_str() when manipulating strings
  tracing, RAS: Cleanup on __get_str() usage
  tracing: Use outer () on __get_str() definition
  ftrace: Reduce size of function graph entries
  tracing: Have HIST_TRIGGERS select TRACING
  tracing: Using for_each_set_bit() to simplify trace_pid_write()
  ftrace: Move toplevel init out of ftrace_init_tracefs()
  tracing/function_graph: Fix filters for function_graph threshold
  tracing: Skip more functions when doing stack tracing of events
  tracing: Expose CPU physical addresses (resource values) for PCI devices
  tracing: Show the preempt count of when the event was called
  tracing: Add trace_printk sample code
  tracing: Choose static tp_printk buffer by explicit nesting count
  tracing: expose current->comm to [ku]probe events
  ftrace: Have set_ftrace_pid use the bitmap like events do
  tracing: Move pid_list write processing into its own function
  tracing: Move the pid_list seq_file functions to be global
  tracing: Move filtered_pid helper functions into trace.c
  tracing: Make the pid filtering helper functions global

1 files changed, 33 insertions, 0 deletions

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 1d372fa6fefb..74e80a582c28 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -218,6 +218,28 @@ free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 	kfree(data);
 }
 
+void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
+					  void *data, void *dest)
+{
+	int maxlen = get_rloc_len(*(u32 *)dest);
+	u8 *dst = get_rloc_data(dest);
+	long ret;
+
+	if (!maxlen)
+		return;
+
+	ret = strlcpy(dst, current->comm, maxlen);
+	*(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
+}
+NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
+
+void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
+					       void *data, void *dest)
+{
+	*(u32 *)dest = strlen(current->comm) + 1;
+}
+NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
+
 static const struct fetch_type *find_fetch_type(const char *type,
 						const struct fetch_type *ftbl)
 {
@@ -348,6 +370,11 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 			}
 		} else
 			ret = -EINVAL;
+	} else if (strcmp(arg, "comm") == 0) {
+		if (strcmp(t->name, "string") != 0 &&
+		    strcmp(t->name, "string_size") != 0)
+			return -EINVAL;
+		f->fn = t->fetch[FETCH_MTD_comm];
 	} else
 		ret = -EINVAL;
 
@@ -522,6 +549,12 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 		arg[t - parg->comm] = '\0';
 		t++;
 	}
+	/*
+	 * The default type of $comm should be "string", and it can't be
+	 * dereferenced.
+	 */
+	if (!t && strcmp(arg, "$comm") == 0)
+		t = "string";
 	parg->type = find_fetch_type(t, ftbl);
 	if (!parg->type) {
 		pr_info("Unsupported type: %s\n", t);