Fixup for 513950.
Problem:
'blktrace -d <device> -k' does not kill a running
backgound trace. Executing 'blktrace -d <device> -k'
for the second time results in "BLKTRACETEARDOWN:
Invalid argument" message and then each run of
blktrace on that machine prints the following output:
BLKTRACESETUP: No such file or directory.
The bug:
The option -k results in clobbering information
about running trace by kernel (blk_trace_remove),
while resources (files open in debugfs by the running
background blktrace) are not released.
Solution:
. Disable non-working "kill" option;
. Update documentation, advise to send SIGINT signal
via kill(1) to the running background blktrace for
its correct termination.
Signed-off-by: Edward Shishkin <edward@xxxxxxxxxx>
---
blktrace.c | 14 +++++++++++++-
doc/blktrace.8 | 24 ++++--------------------
2 files changed, 17 insertions(+), 21 deletions(-)
--- blktrace.orig/blktrace.c
+++ blktrace/blktrace.c
@@ -64,6 +64,7 @@
#define DEBUGFS_TYPE (0x64626720)
#define TRACE_NET_PORT (8462)
+#define KILL_OPT_ENABLED (0)
enum {
Net_none = 0,
@@ -326,7 +327,12 @@ static int *cl_fds;
static int (*handle_pfds)(struct tracer *, int, int);
static int (*handle_list)(struct tracer_devpath_head *, struct list_head *);
+#if KILL_OPT_ENABLED
#define S_OPTS "d:a:A:r:o:kw:vVb:n:D:lh:p:sI:"
+#else
+#define S_OPTS "d:a:A:r:o:w:vVb:n:D:lh:p:sI:"
+#endif /* KILL_OPT_ENABLED */
+
static struct option l_opts[] = {
{
.name = "dev",
@@ -364,12 +370,14 @@ static struct option l_opts[] = {
.flag = NULL,
.val = 'o'
},
+#if KILL_OPT_ENABLED
{
.name = "kill",
.has_arg = no_argument,
.flag = NULL,
.val = 'k'
},
+#endif /* KILL_OPT_ENABLED */
{
.name = "stopwatch",
.has_arg = required_argument,
@@ -442,7 +450,9 @@ static char usage_str[] = \
"\t-r Path to mounted debugfs, defaults to /sys/kernel/debug\n" \
"\t-o File(s) to send output to\n" \
"\t-D Directory to prepend to output file names\n" \
- "\t-k Kill a running trace\n" \
+#if KILL_OPT_ENABLED
+ "\t-k Kill a running trace\n" \
+#endif /* KILL_OPT_ENABLED */
"\t-w Stop after defined time, in seconds\n" \
"\t-a Only trace specified actions. See documentation\n" \
"\t-A Give trace mask as a single value. See documentation\n" \
@@ -2065,9 +2075,11 @@ static int handle_args(int argc, char *a
case 'o':
output_name = optarg;
break;
+#if KILL_OPT_ENABLED
case 'k':
kill_running_trace = 1;
break;
+#endif /* KILL_OPT_ENABLED */
case 'w':
stop_watch = atoi(optarg);
if (stop_watch <= 0) {
--- blktrace.orig/doc/blktrace.8
+++ blktrace/doc/blktrace.8
@@ -66,19 +66,10 @@ blktrace may also be run concurrently wi
.TP 2
\-
The default behaviour for blktrace is to run forever until explicitly
-killed by the user (via a control-C, or kill utility invocation).
-There are two ways to modify this:
-
-.TP 5
- 1.
-You may utilise the blktrace utility itself to kill
-a running trace -- via the \fB\-k\fR option.
-
-.TP 5
- 2.
-You can specify a run-time duration for blktrace via the
-\fB\-w\fR option -- then blktrace will run for the specified number
-of seconds, and then halt.
+killed by the user (via a control-C, or sending SIGINT signal to the
+process via invocation the kill (1) utility). Also you can specify a
+run-time duration for blktrace via the \fB\-w\fR option -- then
+blktrace will run for the specified number of seconds, and then halt.
.SH OPTIONS
@@ -119,13 +110,6 @@ Adds \fIdev\fR as a device to trace
Adds the devices found in \fIfile\fR as devices to trace
.RE
-\-k
-.br
-\-\-kill
-.RS
-Kill on-going trace
-.RE
-
\-n \fInum\-sub\fR
.br
\-\-num\-sub=\fInum-sub\fR
