Hi Ingo,
Could you please collect this patch? It fixes a bug which prevent unwind for
ARM.
Thank you.
On 2015/3/13 17:44, Namhyung Kim wrote:
> Hi Wang,
>
> On Fri, Mar 13, 2015 at 03:02:56PM +0800, Wang Nan wrote:
>> Commit f1f13af99a90 ("perf callchain: Cache eh/debug frame offset for
>> dwarf unwind") introduces a cache for .debug_frame and .eh_frame_hdr.
>> Unfortunately, it makes them share a same cache (dso->frame_offset).
>> Which causes unwind failure on ARM:
>>
>> $ perf test unwind
>> Test dwarf unwind: FAILED!
>>
>> The reason is that, if a dso has '.debug_frame' but doesn't have
>> '.eh_frame_hdr' (like ARM), dso->frame_offset will be filled by offset
>> of '.debug_frame' during the first time calling of find_proc_info() ->
>> read_unwind_spec_debug_frame(), and be regarded to '.eh_frame_hdr' when
>> the second time calling of find_proc_info() ->
>> read_unwind_spec_eh_frame(), since '.eh_frame_hdr' is checked prior to
>> '.debug_frame'.
>>
>> This patch solves the problem by creating two cache fields for
>> '.eh_frame_hdr' and '.debug_frame'.
>>
>> Signed-off-by: Wang Nan <wangn...@huawei.com>
>
> Acked-by: Namhyung Kim <namhy...@kernel.org>
>
> Thanks,
> Namhyung
>
>
>> ---
>> tools/perf/util/dso.h | 3 ++-
>> tools/perf/util/unwind-libunwind.c | 8 ++++----
>> 2 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
>> index ced9284..408c65f 100644
>> --- a/tools/perf/util/dso.h
>> +++ b/tools/perf/util/dso.h
>> @@ -139,7 +139,8 @@ struct dso {
>> u32 status_seen;
>> size_t file_size;
>> struct list_head open_entry;
>> - u64 frame_offset;
>> + u64 debug_frame_offset;
>> + u64 eh_frame_hdr_offset;
>> } data;
>>
>> union { /* Tool specific area */
>> diff --git a/tools/perf/util/unwind-libunwind.c
>> b/tools/perf/util/unwind-libunwind.c
>> index e3c40a5..7b09a44 100644
>> --- a/tools/perf/util/unwind-libunwind.c
>> +++ b/tools/perf/util/unwind-libunwind.c
>> @@ -266,7 +266,7 @@ static int read_unwind_spec_eh_frame(struct dso *dso,
>> struct machine *machine,
>> u64 *fde_count)
>> {
>> int ret = -EINVAL, fd;
>> - u64 offset = dso->data.frame_offset;
>> + u64 offset = dso->data.eh_frame_hdr_offset;
>>
>> if (offset == 0) {
>> fd = dso__data_fd(dso, machine);
>> @@ -275,7 +275,7 @@ static int read_unwind_spec_eh_frame(struct dso *dso,
>> struct machine *machine,
>>
>> /* Check the .eh_frame section for unwinding info */
>> offset = elf_section_offset(fd, ".eh_frame_hdr");
>> - dso->data.frame_offset = offset;
>> + dso->data.eh_frame_hdr_offset = offset;
>> }
>>
>> if (offset)
>> @@ -291,7 +291,7 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
>> struct machine *machine, u64 *offset)
>> {
>> int fd;
>> - u64 ofs = dso->data.frame_offset;
>> + u64 ofs = dso->data.debug_frame_offset;
>>
>> if (ofs == 0) {
>> fd = dso__data_fd(dso, machine);
>> @@ -300,7 +300,7 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
>>
>> /* Check the .debug_frame section for unwinding info */
>> ofs = elf_section_offset(fd, ".debug_frame");
>> - dso->data.frame_offset = ofs;
>> + dso->data.debug_frame_offset = ofs;
>> }
>>
>> *offset = ofs;
>> --
>> 1.8.3.4
>>
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