Re: [PATCH perf/core 01/13] perf probe: Fix to free temporal Dwarf_Frame

From: Namhyung Kim
Date: Wed Nov 18 2015 - 18:38:28 EST


On November 19, 2015 7:36:39 AM GMT+09:00, Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
>Em Wed, Nov 18, 2015 at 03:40:12PM +0900, Masami Hiramatsu escreveu:
>> Since dwarf_cfi_addrframe returns malloc'd Dwarf_Frame
>> object, it has to be freed after used.
>
>Applied to perf/urgent
>
>> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
>> ---
>> tools/perf/util/probe-finder.c | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/perf/util/probe-finder.c
>b/tools/perf/util/probe-finder.c
>> index 63993d7..4d7d4f4 100644
>> --- a/tools/perf/util/probe-finder.c
>> +++ b/tools/perf/util/probe-finder.c
>> @@ -683,21 +683,24 @@ static int call_probe_finder(Dwarf_Die *sc_die,
>struct probe_finder *pf)
>> ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops,
>&nops, 1);
>> if (ret <= 0 || nops == 0) {
>> pf->fb_ops = NULL;
>> + ret = 0;
>> #if _ELFUTILS_PREREQ(0, 142)
>> } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa
>&&
>> pf->cfi != NULL) {
>> - Dwarf_Frame *frame;
>> + Dwarf_Frame *frame = NULL;
>> if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
>> dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {

What if dwarf_cfi_addrframe() succeeded but
dwarf_frame_cfa() failed? It seems that the frame
still can be leaked..

Thanks
Namhyung


>> pr_warning("Failed to get call frame on 0x%jx\n",
>> (uintmax_t)pf->addr);
>> - return -ENOENT;
>> + ret = -ENOENT;
>> }
>> + free(frame);
>> #endif
>> }
>>
>> /* Call finder's callback handler */
>> - ret = pf->callback(sc_die, pf);
>> + if (ret >= 0)
>> + ret = pf->callback(sc_die, pf);
>>
>> /* *pf->fb_ops will be cached in libdw. Don't free it. */
>> pf->fb_ops = NULL;

Hi Arnaldo and Masami,
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/