From: rostedt@goodmis.org (Steven Rostedt)
Subject: [PATCH v7 00/16] tracing: probeevent: Improve fetcharg features
Date: Thu, 3 May 2018 18:11:37 -0400 [thread overview]
Message-ID: <20180503181137.6d82d897@gandalf.local.home> (raw)
Message-ID: <20180503221137.lMmymqjKah1PwikW6sr2RCk3vgu0fmpc4V03JGSCEf0@z> (raw)
In-Reply-To: <152465856498.26224.16969986455942749517.stgit@devbox>
On Wed, 25 Apr 2018 21:16:06 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> Hi,
>
> This is the 7th version of the fetch-arg improvement series.
> This includes variable changes on fetcharg framework like,
>
> - Add fetcharg testcases (syntax, argN, symbol, string and array)
> and probepoint testcase.
> - Rewrite fetcharg framework with fetch_insn, switch-case based
> instead of function pointer.
> - Add "symbol" type support, which shows symbol+offset instead of
> address value.
> - Add "$argN" fetcharg, which fetches function parameters.
> (currently only for x86-64)
> - Add array type support (including string arrary :) ) ,
> which enables to get fixed length array from probe-events.
> - Add array type support for perf-probe, so that user can
> dump partial array entries.
>
> V6 is here:
> https://lkml.org/lkml/2018/3/17/75
>
> Changes from the v6 are here:
> [6/16] - Fix to return an error if failed to fetch string and
> fill zero-length data_loc in error case.
> [11/16] - Update document for restructured text.
> [15/16] - Fix README test.
> [16/16] - Add type-casting description (and note) to documentation.
>
> And rebased on the latest Steve's ftrace/core branch.
>
Hi Masami,
I skimmed through the patches and it they appear fine. I've applied
them and started playing a little.
I've been thinking my function based events, and thought instead I
would make them part of the kprobe infrastructure. Just have a slightly
different format, and instead of being p: or r: be f: And keep the
format I was suggesting.
What do you think?
Also, when looking at the kprobe code, I was looking at this function:
> /* Ftrace callback handler for kprobes -- called under preepmt disabed */
> void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
> struct ftrace_ops *ops, struct pt_regs *regs)
> {
> struct kprobe *p;
> struct kprobe_ctlblk *kcb;
>
> /* Preempt is disabled by ftrace */
> p = get_kprobe((kprobe_opcode_t *)ip);
> if (unlikely(!p) || kprobe_disabled(p))
> return;
>
> kcb = get_kprobe_ctlblk();
> if (kprobe_running()) {
> kprobes_inc_nmissed_count(p);
> } else {
> unsigned long orig_ip = regs->ip;
> /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
> regs->ip = ip + sizeof(kprobe_opcode_t);
>
> /* To emulate trap based kprobes, preempt_disable here */
> preempt_disable();
> __this_cpu_write(current_kprobe, p);
> kcb->kprobe_status = KPROBE_HIT_ACTIVE;
> if (!p->pre_handler || !p->pre_handler(p, regs)) {
> __skip_singlestep(p, regs, kcb, orig_ip);
> preempt_enable_no_resched();
This preemption disabling and enabling looks rather strange. Looking at
git blame, it appears this was added for jprobes. Can we remove it now
that jprobes is going away?
> }
> /*
> * If pre_handler returns !0, it sets regs->ip and
> * resets current kprobe, and keep preempt count +1.
> */
> }
> }
-- Steve
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next prev parent reply other threads:[~2018-05-03 22:11 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-25 12:16 [PATCH v7 00/16] tracing: probeevent: Improve fetcharg features mhiramat
2018-04-25 12:16 ` Masami Hiramatsu
2018-04-25 12:16 ` [PATCH v7 01/16] tracing: probeevent: Cleanup print argument functions mhiramat
2018-04-25 12:16 ` Masami Hiramatsu
2018-04-25 12:17 ` [PATCH v7 02/16] tracing: probeevent: Cleanup argument field definition mhiramat
2018-04-25 12:17 ` Masami Hiramatsu
2018-04-25 12:17 ` [PATCH v7 03/16] tracing: probeevent: Remove NOKPROBE_SYMBOL from print functions mhiramat
2018-04-25 12:17 ` Masami Hiramatsu
2018-04-25 12:18 ` [PATCH v7 04/16] tracing: probeevent: Introduce new argument fetching code mhiramat
2018-04-25 12:18 ` Masami Hiramatsu
2018-04-25 12:18 ` [PATCH v7 05/16] tracing: probeevent: Unify fetch type tables mhiramat
2018-04-25 12:18 ` Masami Hiramatsu
2018-04-25 12:19 ` [PATCH v7 06/16] tracing: probeevent: Return consumed bytes of dynamic area mhiramat
2018-04-25 12:19 ` Masami Hiramatsu
2018-04-25 12:19 ` [PATCH v7 07/16] tracing: probeevent: Append traceprobe_ for exported function mhiramat
2018-04-25 12:19 ` Masami Hiramatsu
2018-04-25 12:19 ` [PATCH v7 08/16] tracing: probeevent: Unify fetch_insn processing common part mhiramat
2018-04-25 12:19 ` Masami Hiramatsu
2018-04-25 12:20 ` [PATCH v7 09/16] tracing: probeevent: Add symbol type mhiramat
2018-04-25 12:20 ` Masami Hiramatsu
2018-04-25 12:20 ` [PATCH v7 10/16] x86: ptrace: Add function argument access API mhiramat
2018-04-25 12:20 ` Masami Hiramatsu
2018-04-25 12:21 ` [PATCH v7 11/16] tracing: probeevent: Add $argN for accessing function args mhiramat
2018-04-25 12:21 ` Masami Hiramatsu
2018-04-25 12:21 ` [PATCH v7 12/16] tracing: probeevent: Add array type support mhiramat
2018-04-25 12:21 ` Masami Hiramatsu
2018-04-25 12:22 ` [PATCH v7 13/16] selftests: ftrace: Add a testcase for symbol type mhiramat
2018-04-25 12:22 ` Masami Hiramatsu
2018-04-25 12:22 ` [PATCH v7 14/16] selftests: ftrace: Add a testcase for $argN with kprobe_event mhiramat
2018-04-25 12:22 ` Masami Hiramatsu
2018-04-25 12:23 ` [PATCH v7 15/16] selftests: ftrace: Add a testcase for array type " mhiramat
2018-04-25 12:23 ` Masami Hiramatsu
2018-04-25 12:23 ` [PATCH v7 16/16] perf-probe: Add array argument support mhiramat
2018-04-25 12:23 ` Masami Hiramatsu
2018-04-27 1:42 ` [PATCH v7 00/16] tracing: probeevent: Improve fetcharg features rostedt
2018-04-27 1:42 ` Steven Rostedt
2018-05-03 22:11 ` rostedt [this message]
2018-05-03 22:11 ` Steven Rostedt
2018-05-04 15:48 ` mhiramat
2018-05-04 15:48 ` Masami Hiramatsu
2018-05-04 16:06 ` rostedt
2018-05-04 16:06 ` Steven Rostedt
2018-05-04 17:30 ` naveen.n.rao
2018-05-04 17:30 ` Naveen N. Rao
2018-05-05 2:38 ` mhiramat
2018-05-05 2:38 ` Masami Hiramatsu
2018-05-05 7:46 ` naveen.n.rao
2018-05-05 7:46 ` Naveen N. Rao
2018-05-05 14:32 ` mhiramat
2018-05-05 14:32 ` Masami Hiramatsu
2018-05-07 8:11 ` naveen.n.rao
2018-05-07 8:11 ` Naveen N. Rao
2018-05-07 14:53 ` mhiramat
2018-05-07 14:53 ` Masami Hiramatsu
2018-05-08 10:11 ` naveen.n.rao
2018-05-08 10:11 ` Naveen N. Rao
2018-05-08 15:02 ` mhiramat
2018-05-08 15:02 ` Masami Hiramatsu
2018-05-08 18:01 ` naveen.n.rao
2018-05-08 18:01 ` Naveen N. Rao
2018-05-05 15:51 ` mhiramat
2018-05-05 15:51 ` Masami Hiramatsu
2018-05-07 15:30 ` rostedt
2018-05-07 15:30 ` Steven Rostedt
2018-05-08 4:01 ` mhiramat
2018-05-08 4:01 ` Masami Hiramatsu
2018-05-07 15:21 ` rostedt
2018-05-07 15:21 ` Steven Rostedt
2018-06-21 20:16 ` rostedt
2018-06-21 20:16 ` Steven Rostedt
2018-06-22 6:04 ` mhiramat
2018-06-22 6:04 ` Masami Hiramatsu
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