Merge tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

torvalds · torvalds · commit b6ea7bcf7783 · 2019-02-13T10:28:17.000-08:00
Pull tracing fix from Steven Rostedt:
 "This fixes kprobes/uprobes dynamic processing of strings, where it
  processes the args but does not update the remaining length of the
  buffer that the string arguments will be placed in. It constantly
  passes in the total size of buffer used instead of passing in the
  remaining size of the buffer used.

  This could cause issues if the strings are larger than the max size of
  an event which could cause the strings to be written beyond what was
  reserved on the buffer"

* tag 'trace-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: probeevent: Correctly update remaining space in dynamic area
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
@@ -180,10 +180,12 @@ store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs,
 		if (unlikely(arg->dynamic))
 			*dl = make_data_loc(maxlen, dyndata - base);
 		ret = process_fetch_insn(arg->code, regs, dl, base);
-		if (unlikely(ret < 0 && arg->dynamic))
+		if (unlikely(ret < 0 && arg->dynamic)) {
 			*dl = make_data_loc(0, dyndata - base);
-		else
+		} else {
 			dyndata += ret;
+			maxlen -= ret;
+		}
 	}
 }
 

Original file line number	Diff line number	Diff line change
`@@ -180,10 +180,12 @@ store_trace_args(void data, struct trace_probe tp, struct pt_regs *regs,`
`180`	`180`	`if (unlikely(arg->dynamic))`
`181`	`181`	`*dl = make_data_loc(maxlen, dyndata - base);`
`182`	`182`	`ret = process_fetch_insn(arg->code, regs, dl, base);`
`183`		`- if (unlikely(ret < 0 && arg->dynamic))`
	`183`	`+ if (unlikely(ret < 0 && arg->dynamic)) {`
`184`	`184`	`*dl = make_data_loc(0, dyndata - base);`
`185`		`- else`
	`185`	`+ } else {`
`186`	`186`	`dyndata += ret;`
	`187`	`+ maxlen -= ret;`
	`188`	`+ }`
`187`	`189`	`}`
`188`	`190`	`}`
`189`	`191`