linux/samples
Steven Rostedt (Red Hat) d6726c8145 tracing: Fix sample output of dynamic arrays
He Kuang noticed that the trace event samples for arrays was broken:

"The output result of trace_foo_bar event in traceevent samples is
 wrong. This problem can be reproduced as following:

  (Build kernel with SAMPLE_TRACE_EVENTS=m)

  $ insmod trace-events-sample.ko

  $ echo 1 > /sys/kernel/debug/tracing/events/sample-trace/foo_bar/enable

  $ cat /sys/kernel/debug/tracing/trace

  event-sample-980 [000] ....  43.649559: foo_bar: foo hello 21 0x15
  BIT1|BIT3|0x10 {0x1,0x6f6f6e53,0xff007970,0xffffffff} Snoopy
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 The array length is not right, should be {0x1}.
  (ffffffff,ffffffff)

  event-sample-980 [000] ....  44.653827: foo_bar: foo hello 22 0x16
  BIT2|BIT3|0x10
  {0x1,0x2,0x646e6147,0x666c61,0xffffffff,0xffffffff,0x750aeffe,0x7}
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 The array length is not right, should be {0x1,0x2}.
  Gandalf (ffffffff,ffffffff)"

This was caused by an update to have __print_array()'s second parameter
be the count of items in the array and not the size of the array.

As there is already users of __print_array(), it can not change. But
the sample code can and we can also improve on the documentation about
__print_array() and __get_dynamic_array_len().

Link: http://lkml.kernel.org/r/1436839171-31527-2-git-send-email-hekuang@huawei.com

Fixes: ac01ce1410 ("tracing: Make ftrace_print_array_seq compute buf_len")
Reported-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-07-17 14:15:13 -04:00
..
bpf bpf: BPF based latency tracing 2015-06-23 06:09:58 -07:00
hidraw HID: samples/hidraw: make it possible to select device 2015-03-15 10:11:21 -04:00
hw_breakpoint
kdb
kfifo kfifo API type safety 2013-11-15 09:32:23 +09:00
kobject samples/kobject: be explicit in the module license 2015-03-25 13:41:42 +01:00
kprobes kprobes: update jprobe_example.c for do_fork() change 2014-09-26 11:11:12 +02:00
livepatch livepatch: rename config to CONFIG_LIVEPATCH 2015-02-04 11:25:51 +01:00
pktgen pktgen: add benchmark script pktgen_bench_xmit_mode_netif_receive.sh 2015-05-22 23:59:17 -04:00
rpmsg
seccomp samples/seccomp: improve label helper 2015-02-17 14:34:55 -08:00
trace_events tracing: Fix sample output of dynamic arrays 2015-07-17 14:15:13 -04:00
uhid
Kconfig livepatch: rename config to CONFIG_LIVEPATCH 2015-02-04 11:25:51 +01:00
Makefile livepatch: samples: add sample live patching module 2014-12-22 15:40:49 +01:00