Commit be07afe9 authored Aug 26, 2015 by Wang Nan Committed by Arnaldo Carvalho de Melo Aug 26, 2015

perf probe: Fix list result when address is zero



When manually added uprobe point with zero address, 'perf probe -l'
reports error. For example:

  # echo p:probe_libc/abs_0 /path/to/lib.bin:0x0 arg1=%ax > \
           /sys/kernel/debug/tracing/uprobe_events

  # perf probe -l
  Error: Failed to show event list.

Probing at 0x0 is possible and useful when lib.bin is not a normal
shared object but is manually mapped. However, in this case kernel
report:

  # cat /sys/kernel/debug/tracing/uprobe_events
  p:probe_libc/abs_0 /path/to/lib.bin:0x          (null) arg1=%ax

This patch supports the above kernel output.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440586666-235233-5-git-send-email-wangnan0@huawei.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 614e2fdb

tools/perf/util/probe-event.c

+25 −3

Original line number	Diff line number	Diff line
		@@ -1519,9 +1519,31 @@ int parse_probe_trace_command(const char cmd, struct probe_trace_event tev)
		} else
		p = argv[1];
		fmt1_str = strtok_r(p, "+", &fmt);
		if (fmt1_str[0] == '0') /* only the address started with 0x */
		/* only the address started with 0x */
		if (fmt1_str[0] == '0') {
		/*
		* Fix a special case:
		* if address == 0, kernel reports something like:
		* p:probe_libc/abs_0 /lib/libc-2.18.so:0x (null) arg1=%ax
		* Newer kernel may fix that, but we want to
		* support old kernel also.
		*/
		if (strcmp(fmt1_str, "0x") == 0) {
		if (!argv[2] \|\| strcmp(argv[2], "(null)")) {
		ret = -EINVAL;
		goto out;
		}
		tp->address = 0;

		free(argv[2]);
		for (i = 2; argv[i + 1] != NULL; i++)
		argv[i] = argv[i + 1];

		argv[i] = NULL;
		argc -= 1;
		} else
		tp->address = strtoul(fmt1_str, NULL, 0);
		else {
		} else {
		/* Only the symbol-based probe has offset */
		tp->symbol = strdup(fmt1_str);
		if (tp->symbol == NULL) {