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perf probe: Skip overlapped location on searching variables 

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 1a375ae765
("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: cf6eb489e5 ("perf probe: Show accessible local variables")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157241938927.32002.4026859017790562751.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu 2019-10-30 16:09:49 +09:00 committed by Arnaldo Carvalho de Melo
parent 86c0bf8539
commit dee36a2abb
1 changed files with 20 additions and 0 deletions
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20
tools/perf/util/probe-finder.c
View File

@ -1428,6 +1428,18 @@ 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)
{
@ -1438,6 +1450,14 @@ 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);