LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Masami Hiramatsu <mhiramat@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [BUGFIX PATCH 4/4] perf probe: Skip overlapped location on searching variables
Date: Wed, 30 Oct 2019 16:09:49 +0900
Message-ID: <157241938927.32002.4026859017790562751.stgit@devnote2> (raw)
In-Reply-To: <157241935028.32002.10228194508152968737.stgit@devnote2>

Since debuginfo__find_probes() callback function can be called
with  the location which already passed, the callback function
must filter out such overlapped locations.

add_probe_trace_event() has already done it by commit 1a375ae7659a
("perf probe: Skip same probe address for a given line"), but
add_available_vars() doesn't. Thus perf probe -v shows same address
repeatedly as below.

  # perf probe -V vfs_read:18
  Available variables at vfs_read:18
          @<vfs_read+217>
                  char*   buf
                  loff_t* pos
                  ssize_t ret
                  struct file*    file
          @<vfs_read+217>
                  char*   buf
                  loff_t* pos
                  ssize_t ret
                  struct file*    file
          @<vfs_read+226>
                  char*   buf
                  loff_t* pos
                  ssize_t ret
                  struct file*    file


With this fix, perf probe -V shows it correctly.
  # perf probe -V vfs_read:18
  Available variables at vfs_read:18
          @<vfs_read+217>
                  char*   buf
                  loff_t* pos
                  ssize_t ret
                  struct file*    file
          @<vfs_read+226>
                  char*   buf
                  loff_t* pos
                  ssize_t ret
                  struct file*    file

Fixes: cf6eb489e5c0 ("perf probe: Show accessible local variables")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/perf/util/probe-finder.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 88e17a4f5ac3..f441e0174334 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -1413,6 +1413,18 @@ static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
 	return DIE_FIND_CB_END;
 }
 
+static bool available_var_finder_overlap(struct available_var_finder *af)
+{
+	int i;
+
+	for (i = 0; i < af->nvls; i++) {
+		if (af->pf.addr == af->vls[i].point.address)
+			return true;
+	}
+	return false;
+
+}
+
 /* Add a found vars into available variables list */
 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 {
@@ -1423,6 +1435,14 @@ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
 	Dwarf_Die die_mem;
 	int ret;
 
+	/*
+	 * For some reason (e.g. different column assigned to same address),
+	 * this callback can be called with the address which already passed.
+	 * Ignore it first.
+	 */
+	if (available_var_finder_overlap(af))
+		return 0;
+
 	/* Check number of tevs */
 	if (af->nvls == af->max_vls) {
 		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-30  7:09 [BUGFIX PATCH 0/4] perf probe: Fixes bugs in show-lines and show vars etc Masami Hiramatsu
2019-10-30  7:09 ` [BUGFIX PATCH 1/4] perf probe: Skip end-of-sequence and non statement lines Masami Hiramatsu
2019-11-06 20:04   ` Arnaldo Carvalho de Melo
2020-01-10  9:29     ` Rantala, Tommi T. (Nokia - FI/Espoo)
2020-01-10 15:43       ` Masami Hiramatsu
2019-11-12 11:17   ` [tip: perf/core] " tip-bot2 for Masami Hiramatsu
2019-10-30  7:09 ` [BUGFIX PATCH 2/4] perf probe: Filter out instances except for inlined subroutine and subprogram Masami Hiramatsu
2019-11-06 20:06   ` Arnaldo Carvalho de Melo
2019-11-12 11:17   ` [tip: perf/core] " tip-bot2 for Masami Hiramatsu
2019-10-30  7:09 ` [BUGFIX PATCH 3/4] perf probe: Fix to show calling lines of inlined functions Masami Hiramatsu
2019-11-06 20:08   ` Arnaldo Carvalho de Melo
2019-11-12 11:17   ` [tip: perf/core] " tip-bot2 for Masami Hiramatsu
2019-10-30  7:09 ` Masami Hiramatsu [this message]
2019-11-06 20:09   ` [BUGFIX PATCH 4/4] perf probe: Skip overlapped location on searching variables Arnaldo Carvalho de Melo
2019-11-12 11:17   ` [tip: perf/core] " tip-bot2 for Masami Hiramatsu

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=157241938927.32002.4026859017790562751.stgit@devnote2 \
    --to=mhiramat@kernel.org \
    --cc=acme@kernel.org \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=namhyung@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git