Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [BUGFIX PATCH 4/4] perf probe: Skip overlapped location on searching variables | Date | Wed, 30 Oct 2019 16:09:49 +0900 |
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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);
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