(2015/04/25 17:08), He Kuang wrote:
> There are missing curly braces which causes find_variable() return wrong
> value when probing with global variables.
>
> This problem can be reproduced as following:
>
> $ perf probe -v --add='generic_perform_write global_variable_for_test'
> ...
> Try to find probe point from debuginfo.
> Probe point found: generic_perform_write+0
> Searching 'global_variable_for_test' variable in context.
> An error occurred in debuginfo analysis (-2).
> Error: Failed to add events. Reason: No such file or directory (Code: -2)
>
> After this patch:
>
> $ perf probe -v --add='generic_perform_write global_variable_for_test'
> ...
> Converting variable global_variable_for_test into trace event.
> global_variable_for_test type is int.
> Found 1 probe_trace_events.
> Opening /sys/kernel/debug/tracing/kprobe_events write=1
> Added new event:
> Writing event: p:probe/generic_perform_write _stext+1237464
> global_variable_for_test=@global_variable_for_test+0:s32
> probe:generic_perform_write (on generic_perform_write with
> global_variable_for_test)
>
> You can now use it in all perf tools, such as:
>
> perf record -e probe:generic_perform_write -aR sleep 1
Oops, that's my fault! :(
Acked-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Thank you!!
>
> Signed-off-by: He Kuang <heku...@huawei.com>
> ---
> tools/perf/util/probe-finder.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 44554c3..1c3cc07 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -578,10 +578,12 @@ static int find_variable(Dwarf_Die *sc_die, struct
> probe_finder *pf)
> /* Search child die for local variables and parameters. */
> if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
> /* Search again in global variables */
> - if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0,
> &vr_die))
> + if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
> + 0, &vr_die)) {
> pr_warning("Failed to find '%s' in this function.\n",
> pf->pvar->var);
> ret = -ENOENT;
> + }
> }
> if (ret >= 0)
> ret = convert_variable(&vr_die, pf);
>
--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu...@hitachi.com
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