From ec3a9039601af210fca4650d229621fe5a21df0b Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 5 Jan 2010 17:46:41 -0500 Subject: tracing/kprobe: Update example output in documentation Update example output in documentation according to current implementation. Signed-off-by: Masami Hiramatsu Cc: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo Cc: systemtap Cc: DLE Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <20100105224641.19431.34967.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- Documentation/trace/kprobetrace.txt | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) (limited to 'Documentation/trace') diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 47aabeebbdf..c3eff6ff945 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -97,23 +97,24 @@ recording return value as "myretprobe" event. cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format name: myprobe -ID: 75 +ID: 780 format: - field:unsigned short common_type; offset:0; size:2; - field:unsigned char common_flags; offset:2; size:1; - field:unsigned char common_preempt_count; offset:3; size:1; - field:int common_pid; offset:4; size:4; - field:int common_tgid; offset:8; size:4; - - field: unsigned long ip; offset:16;tsize:8; - field: int nargs; offset:24;tsize:4; - field: unsigned long dfd; offset:32;tsize:8; - field: unsigned long filename; offset:40;tsize:8; - field: unsigned long flags; offset:48;tsize:8; - field: unsigned long mode; offset:56;tsize:8; - -print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->ip, REC->dfd, REC->filename, REC->flags, REC->mode - + field:unsigned short common_type; offset:0; size:2; signed:0; + field:unsigned char common_flags; offset:2; size:1; signed:0; + field:unsigned char common_preempt_count; offset:3; size:1;signed:0; + field:int common_pid; offset:4; size:4; signed:1; + field:int common_lock_depth; offset:8; size:4; signed:1; + + field:unsigned long __probe_ip; offset:12; size:4; signed:0; + field:int __probe_nargs; offset:16; size:4; signed:1; + field:unsigned long dfd; offset:20; size:4; signed:0; + field:unsigned long filename; offset:24; size:4; signed:0; + field:unsigned long flags; offset:28; size:4; signed:0; + field:unsigned long mode; offset:32; size:4; signed:0; + + +print fmt: "(%lx) dfd=%lx filename=%lx flags=%lx mode=%lx", REC->__probe_ip, +REC->dfd, REC->filename, REC->flags, REC->mode You can see that the event has 4 arguments as in the expressions you specified. -- cgit v1.2.3 From 14640106f243a3b29944d7198569090fa6546f2d Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 5 Jan 2010 17:46:48 -0500 Subject: tracing/kprobe: Drop function argument access syntax Drop function argument access syntax, because the function arguments depend on not only architecture but also compile-options and function API. And now, we have perf-probe for finding register/memory assigned to each argument. Signed-off-by: Masami Hiramatsu Cc: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo Cc: systemtap Cc: DLE Cc: Frederic Weisbecker Cc: Steven Rostedt Cc: Roland McGrath Cc: Oleg Nesterov Cc: Mahesh Salgaonkar Cc: Benjamin Herrenschmidt Cc: Michael Neuling Cc: linuxppc-dev@ozlabs.org LKML-Reference: <20100105224648.19431.52309.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- Documentation/trace/kprobetrace.txt | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'Documentation/trace') diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index c3eff6ff945..f30978e001f 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -37,15 +37,12 @@ Synopsis of kprobe_events @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) $stackN : Fetch Nth entry of stack (N >= 0) $stack : Fetch stack address. - $argN : Fetch function argument. (N >= 0)(*) - $retval : Fetch return value.(**) - +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) + $retval : Fetch return value.(*) + +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**) NAME=FETCHARG: Set NAME as the argument name of FETCHARG. - (*) aN may not correct on asmlinkaged functions and at the middle of - function body. - (**) only for return probe. - (***) this is useful for fetching a field of data structures. + (*) only for return probe. + (**) this is useful for fetching a field of data structures. Per-Probe Event Filtering @@ -82,11 +79,14 @@ Usage examples To add a probe as a new event, write a new definition to kprobe_events as below. - echo p:myprobe do_sys_open dfd=$arg0 filename=$arg1 flags=$arg2 mode=$arg3 > /sys/kernel/debug/tracing/kprobe_events + echo p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack) > /sys/kernel/debug/tracing/kprobe_events This sets a kprobe on the top of do_sys_open() function with recording -1st to 4th arguments as "myprobe" event. As this example shows, users can -choose more familiar names for each arguments. +1st to 4th arguments as "myprobe" event. Note, which register/stack entry is +assigned to each function argument depends on arch-specific ABI. If you unsure +the ABI, please try to use probe subcommand of perf-tools (you can find it +under tools/perf/). +As this example shows, users can choose more familiar names for each arguments. echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events @@ -147,4 +147,3 @@ events, you need to enable it. returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel returns from do_sys_open to sys_open+0x1b). - -- cgit v1.2.3 From 580d9e00fdfb85e65c5097dcd739c6efcdbadc96 Mon Sep 17 00:00:00 2001 From: Motohiro KOSAKI Date: Mon, 18 Jan 2010 21:35:05 -0500 Subject: kprobetrace, doc: Shell needs single quote to use $ character Shell interprets $val as shell variable, thus we need quote if we use the echo command. Signed-off-by: KOSAKI Motohiro Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE LKML-Reference: <20100119023505.31880.17367.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar --- Documentation/trace/kprobetrace.txt | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Documentation/trace') diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index f30978e001f..ab57f02e53b 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -79,7 +79,7 @@ Usage examples To add a probe as a new event, write a new definition to kprobe_events as below. - echo p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack) > /sys/kernel/debug/tracing/kprobe_events + echo 'p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)' > /sys/kernel/debug/tracing/kprobe_events This sets a kprobe on the top of do_sys_open() function with recording 1st to 4th arguments as "myprobe" event. Note, which register/stack entry is @@ -88,7 +88,7 @@ the ABI, please try to use probe subcommand of perf-tools (you can find it under tools/perf/). As this example shows, users can choose more familiar names for each arguments. - echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events + echo 'r:myretprobe do_sys_open $retval' >> /sys/kernel/debug/tracing/kprobe_events This sets a kretprobe on the return point of do_sys_open() function with recording return value as "myretprobe" event. -- cgit v1.2.3 From df3ab708b787a2b35de5101452bd51d4a8ae0ded Mon Sep 17 00:00:00 2001 From: Motohiro KOSAKI Date: Mon, 18 Jan 2010 21:35:12 -0500 Subject: kprobetrace, doc: Add the explanation to remove probe points Latest kprobetrace can remove probe points selectively, thus the documentation should be updated too. Signed-off-by: KOSAKI Motohiro Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE LKML-Reference: <20100119023512.31880.35535.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar --- Documentation/trace/kprobetrace.txt | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'Documentation/trace') diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index ab57f02e53b..a9100b28eb8 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -24,6 +24,7 @@ Synopsis of kprobe_events ------------------------- p[:[GRP/]EVENT] SYMBOL[+offs]|MEMADDR [FETCHARGS] : Set a probe r[:[GRP/]EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe + -:[GRP/]EVENT : Clear a probe GRP : Group name. If omitted, use "kprobes" for it. EVENT : Event name. If omitted, the event name is generated @@ -122,6 +123,12 @@ REC->dfd, REC->filename, REC->flags, REC->mode This clears all probe points. + Or, + + echo -:myprobe >> kprobe_events + + This clears probe points selectively. + Right after definition, each event is disabled by default. For tracing these events, you need to enable it. -- cgit v1.2.3