Messages in this thread Patch in this message | | | Date | Fri, 13 Mar 2015 15:02:56 +0800 | From | Wang Nan <> | Subject | [PATCH] perf callchain: separate eh/debug frame offset cache. |
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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 <wangnan0@huawei.com> --- 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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