FM / general

/usr/share/systemtap/examples/general

Name	Size	Mode	Actions
alias_suffixes.meta	724	0644	edit dl rm
alias_suffixes.stp	1060	0755	edit dl rm
also_ran.meta	605	0644	edit dl rm
also_ran.stp	804	0755	edit dl rm
ansi_colors.meta	507	0644	edit dl rm
ansi_colors.stp	716	0755	edit dl rm
ansi_colors2.meta	570	0644	edit dl rm
ansi_colors2.stp	738	0755	edit dl rm
badname.meta	459	0644	edit dl rm
badname.stp	1335	0755	edit dl rm
badname.txt	126	0644	edit dl rm
callgraph.meta	388	0644	edit dl rm
callgraph.stp	212	0755	edit dl rm
callgraph.txt	3700	0644	edit dl rm
click.wav	1290	0644	edit dl rm
cpu_throttle.meta	795	0644	edit dl rm
cpu_throttle.stp	1481	0755	edit dl rm
eventcount.meta	637	0644	edit dl rm
eventcount.stp	6931	0755	edit dl rm
eventcount.txt	1898	0644	edit dl rm
floatingpoint.meta	479	0644	edit dl rm
floatingpoint.stp	517	0644	edit dl rm
floatingpoint.txt	156	0644	edit dl rm
func_time_stats.meta	696	0644	edit dl rm
func_time_stats.stp	520	0755	edit dl rm
func_time_stats.txt	493	0644	edit dl rm
grapher.stp	1286	0755	edit dl rm
graphs.meta	453	0644	edit dl rm
graphs.stp	1499	0755	edit dl rm
helloworld.meta	397	0644	edit dl rm
helloworld.stp	57	0755	edit dl rm
key.meta	319	0644	edit dl rm
key.stp	414	0755	edit dl rm
keyhack.meta	355	0644	edit dl rm
keyhack.stp	288	0755	edit dl rm
measureinterval.meta	1582	0644	edit dl rm
measureinterval.stp	830	0755	edit dl rm
para-callgraph-verbose.meta	879	0644	edit dl rm
para-callgraph-verbose.stp	407	0755	edit dl rm
para-callgraph.meta	756	0644	edit dl rm
para-callgraph.stp	405	0755	edit dl rm
para-callgraph.txt	4415	0644	edit dl rm
py2example.meta	531	0644	edit dl rm
py2example.tcl	79	0644	edit dl rm
py3example.meta	532	0644	edit dl rm
py3example.tcl	79	0644	edit dl rm
pyexample.py	832	0644	edit dl rm
pyexample.stp	216	0644	edit dl rm
regex.meta	504	0644	edit dl rm
regex.stp	491	0755	edit dl rm
return.wav	6584	0644	edit dl rm
sizeof.meta	664	0644	edit dl rm
sizeof.stp	482	0755	edit dl rm
sizeof.txt	100	0644	edit dl rm
sizeof_interactive.meta	816	0644	edit dl rm
sizeof_interactive.stp	572	0644	edit dl rm
sizeof_interactive.txt	154	0644	edit dl rm
socket-events.meta	563	0644	edit dl rm
socket-events.stp	5451	0755	edit dl rm
stopwatches.meta	860	0644	edit dl rm
stopwatches.stp	957	0755	edit dl rm
tcl-funtop.meta	479	0644	edit dl rm
tcl-funtop.stp	817	0755	edit dl rm
tcl-trace.meta	364	0644	edit dl rm
tcl-trace.stp	1037	0755	edit dl rm
varwatch.meta	583	0644	edit dl rm
varwatch.stp	459	0755	edit dl rm
varwatch.txt	2678	0644	edit dl rm
watchdog.meta	922	0644	edit dl rm
watchdog.stp	447	0755	edit dl rm
whythefail.meta	481	0644	edit dl rm
whythefail.stp	2277	0644	edit dl rm
whythefail.txt	3790	0644	edit dl rm

Edit: /usr/share/systemtap/examples/general/whythefail.txt (3790B)

Some sample uses of whythefail.stp:

------------------------------------------------------------------------

Trace failing cases of do_sys_open, the main outer function behind the
the open(2) syscall.

# stap whythefail.stp kernel do_sys_open '$return < 0' -c 'cat /root/no-such-file || true'
cat: /root/no-such-file: No such file or directory

cat[23342] kernel function(do_sys_open) $return: -2
cat[23342] fs/open.c:992 $$vars: dfd=0xffffffffffffff9c filename=0x7ffc0f9546b9 flags=0x8000 mode=? op={...} fd=? tmp=?
cat[23342] fs/open.c:993 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000
cat[23342] fs/open.c:996 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000
cat[23342] fs/open.c:997 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000
cat[23342] fs/open.c:998 $$vars: f=? dfd=0xffffffffffffff9c filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000
cat[23342] fs/open.c:999 $$vars: f=? dfd=0xffffffffffffff9c filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000
cat[23342] fs/open.c:1000 $$vars: f=0xfffffffffffffffe dfd=? filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000
cat[23342] fs/open.c:1001 $$vars: f=0xfffffffffffffffe dfd=? filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000
cat[23342] fs/open.c:1007 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=0xfffffffffffffffe tmp=0xffff88002b21d000
cat[23342] fs/open.c:1008 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=0xfffffffffffffffe tmp=0xffff88002b21d000
cat[23342] fs/open.c:1009 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=? tmp=?
[... 6 other traces ...]

statistics:
entry count: 19
exit-hit count: 7
exit-miss count: 12
statement count: 216

------------------------------------------------------------------------

Take a random sampling of do_select runs.  Print a dummy non-existent
variable at the end, because the default '$$vars' is too long.  Also,
disable overload-prevention since select(2) is very heavily used;
might even need a larger -DMAXMAPENTRIES=num and smaller -DMAXSTRINGLEN=num
set.  Note that the line numbers shown allow a pretty good
after-the-fact trace of what happened.

# stap -g --suppress-time-limits whythefail.stp kernel do_select 'randint(1000)<1' '$foo'
[...]
Xorg.bin[2360] kernel function(do_select) $return: 1
Xorg.bin[2360] fs/select.c:410 $foo: ?
Xorg.bin[2360] fs/select.c:413 $foo: ?
Xorg.bin[2360] fs/select.c:419 $foo: ?
Xorg.bin[2360] fs/select.c:425 $foo: ?
Xorg.bin[2360] fs/select.c:424 $foo: ?
Xorg.bin[2360] fs/select.c:407 $foo: ?
Xorg.bin[2360] fs/select.c:401 $foo: ?
Xorg.bin[2360] fs/select.c:432 $foo: ?
Xorg.bin[2360] fs/select.c:435 $foo: ?
Xorg.bin[2360] fs/select.c:433 $foo: ?
Xorg.bin[2360] fs/select.c:439 $foo: ?
Xorg.bin[2360] fs/select.c:440 $foo: ?
Xorg.bin[2360] fs/select.c:441 $foo: ?
Xorg.bin[2360] fs/select.c:448 $foo: ?
Xorg.bin[2360] fs/select.c:450 $foo: ?
Xorg.bin[2360] fs/select.c:446 $foo: ?
Xorg.bin[2360] fs/select.c:450 $foo: ?
Xorg.bin[2360] fs/select.c:453 $foo: ?
Xorg.bin[2360] fs/select.c:457 $foo: ?
Xorg.bin[2360] fs/select.c:460 $foo: ?
Xorg.bin[2360] fs/select.c:463 $foo: ?
Xorg.bin[2360] fs/select.c:468 $foo: ?
Xorg.bin[2360] fs/select.c:473 $foo: ?
[...]
Xorg.bin[2360] fs/select.c:493 $foo: ?
Xorg.bin[2360] fs/select.c:494 $foo: ?
Xorg.bin[2360] fs/select.c:496 $foo: ?
Xorg.bin[2360] fs/select.c:498 $foo: ?
Xorg.bin[2360] fs/select.c:501 $foo: ?
Xorg.bin[2360] fs/select.c:500 $foo: ?
Xorg.bin[2360] fs/select.c:534 $foo: ?
Xorg.bin[2360] fs/select.c:536 $foo: ?
Xorg.bin[2360] fs/select.c:537 $foo: ?
^C
statistics:
entry count: 9261
exit-hit count: 8
exit-miss count: 9231
statement count: 3427078

Some sample uses of whythefail.stp: ------------------------------------------------------------------------ Trace failing cases of do_sys_open, the main outer function behind the the open(2) syscall. # stap whythefail.stp kernel do_sys_open '$return < 0' -c 'cat /root/no-such-file || true' cat: /root/no-such-file: No such file or directory cat[23342] kernel function(do_sys_open) $return: -2 cat[23342] fs/open.c:992 $$vars: dfd=0xffffffffffffff9c filename=0x7ffc0f9546b9 flags=0x8000 mode=? op={...} fd=? tmp=? cat[23342] fs/open.c:993 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000 cat[23342] fs/open.c:996 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000 cat[23342] fs/open.c:997 $$vars: dfd=0xffffffffffffff9c filename=? flags=0x8000 mode=? op={...} fd=? tmp=0xffff88002b21d000 cat[23342] fs/open.c:998 $$vars: f=? dfd=0xffffffffffffff9c filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000 cat[23342] fs/open.c:999 $$vars: f=? dfd=0xffffffffffffff9c filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000 cat[23342] fs/open.c:1000 $$vars: f=0xfffffffffffffffe dfd=? filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000 cat[23342] fs/open.c:1001 $$vars: f=0xfffffffffffffffe dfd=? filename=? flags=? mode=? op={...} fd=0x3 tmp=0xffff88002b21d000 cat[23342] fs/open.c:1007 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=0xfffffffffffffffe tmp=0xffff88002b21d000 cat[23342] fs/open.c:1008 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=0xfffffffffffffffe tmp=0xffff88002b21d000 cat[23342] fs/open.c:1009 $$vars: dfd=? filename=? flags=? mode=? op={...} fd=? tmp=? [... 6 other traces ...] statistics: entry count: 19 exit-hit count: 7 exit-miss count: 12 statement count: 216 ------------------------------------------------------------------------ Take a random sampling of do_select runs. Print a dummy non-existent variable at the end, because the default '$$vars' is too long. Also, disable overload-prevention since select(2) is very heavily used; might even need a larger -DMAXMAPENTRIES=num and smaller -DMAXSTRINGLEN=num set. Note that the line numbers shown allow a pretty good after-the-fact trace of what happened. # stap -g --suppress-time-limits whythefail.stp kernel do_select 'randint(1000)<1' '$foo' [...] Xorg.bin[2360] kernel function(do_select) $return: 1 Xorg.bin[2360] fs/select.c:410 $foo: ? Xorg.bin[2360] fs/select.c:413 $foo: ? Xorg.bin[2360] fs/select.c:419 $foo: ? Xorg.bin[2360] fs/select.c:425 $foo: ? Xorg.bin[2360] fs/select.c:424 $foo: ? Xorg.bin[2360] fs/select.c:407 $foo: ? Xorg.bin[2360] fs/select.c:401 $foo: ? Xorg.bin[2360] fs/select.c:432 $foo: ? Xorg.bin[2360] fs/select.c:435 $foo: ? Xorg.bin[2360] fs/select.c:433 $foo: ? Xorg.bin[2360] fs/select.c:439 $foo: ? Xorg.bin[2360] fs/select.c:440 $foo: ? Xorg.bin[2360] fs/select.c:441 $foo: ? Xorg.bin[2360] fs/select.c:448 $foo: ? Xorg.bin[2360] fs/select.c:450 $foo: ? Xorg.bin[2360] fs/select.c:446 $foo: ? Xorg.bin[2360] fs/select.c:450 $foo: ? Xorg.bin[2360] fs/select.c:453 $foo: ? Xorg.bin[2360] fs/select.c:457 $foo: ? Xorg.bin[2360] fs/select.c:460 $foo: ? Xorg.bin[2360] fs/select.c:463 $foo: ? Xorg.bin[2360] fs/select.c:468 $foo: ? Xorg.bin[2360] fs/select.c:473 $foo: ? [...] Xorg.bin[2360] fs/select.c:493 $foo: ? Xorg.bin[2360] fs/select.c:494 $foo: ? Xorg.bin[2360] fs/select.c:496 $foo: ? Xorg.bin[2360] fs/select.c:498 $foo: ? Xorg.bin[2360] fs/select.c:501 $foo: ? Xorg.bin[2360] fs/select.c:500 $foo: ? Xorg.bin[2360] fs/select.c:534 $foo: ? Xorg.bin[2360] fs/select.c:536 $foo: ? Xorg.bin[2360] fs/select.c:537 $foo: ? ^C statistics: entry count: 9261 exit-hit count: 8 exit-miss count: 9231 statement count: 3427078