From be96ea8ffa788dccb1ba895cced29db6687c4911 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Fri, 22 Oct 2010 17:25:01 +0200 Subject: [PATCH] perf symbols: Fix issue with binaries using 16-bytes buildids (v2) Buildid can vary in size. According to the man page of ld, buildid can be 160 bits (sha1) or 128 bits (md5, uuid). Perf assumes buildid size of 20 bytes (160 bits) regardless. When dealing with md5 buildids, it would thus read more than needed and that would cause mismatches and samples without symbols. This patch fixes this by taking into account the actual buildid size as encoded int he section header. The leftover bytes are also cleared. This second version fixes a minor issue with the memset() base position. Cc: David S. Miller Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Robert Richter Cc: Stephane Eranian Link: http://lkml.kernel.org/r/4cc1af3c.8ee7d80a.5a28.ffff868e@mx.google.com Signed-off-by: Stephane Eranian Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 870b3b8c649..40eeaf07725 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1170,8 +1170,7 @@ static int dso__load_sym(struct dso *dso, struct map *map, const char *name, if (dso->has_build_id) { u8 build_id[BUILD_ID_SIZE]; - if (elf_read_build_id(elf, build_id, - BUILD_ID_SIZE) != BUILD_ID_SIZE) + if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) goto out_elf_end; if (!dso__build_id_equal(dso, build_id)) @@ -1443,8 +1442,8 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size) ptr = data->d_buf; while (ptr < (data->d_buf + data->d_size)) { GElf_Nhdr *nhdr = ptr; - int namesz = NOTE_ALIGN(nhdr->n_namesz), - descsz = NOTE_ALIGN(nhdr->n_descsz); + size_t namesz = NOTE_ALIGN(nhdr->n_namesz), + descsz = NOTE_ALIGN(nhdr->n_descsz); const char *name; ptr += sizeof(*nhdr); @@ -1453,8 +1452,10 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size) if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == sizeof("GNU")) { if (memcmp(name, "GNU", sizeof("GNU")) == 0) { - memcpy(bf, ptr, BUILD_ID_SIZE); - err = BUILD_ID_SIZE; + size_t sz = min(size, descsz); + memcpy(bf, ptr, sz); + memset(bf + sz, 0, size - sz); + err = descsz; break; } } @@ -1506,7 +1507,7 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size) while (1) { char bf[BUFSIZ]; GElf_Nhdr nhdr; - int namesz, descsz; + size_t namesz, descsz; if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr)) break; @@ -1515,15 +1516,16 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size) descsz = NOTE_ALIGN(nhdr.n_descsz); if (nhdr.n_type == NT_GNU_BUILD_ID && nhdr.n_namesz == sizeof("GNU")) { - if (read(fd, bf, namesz) != namesz) + if (read(fd, bf, namesz) != (ssize_t)namesz) break; if (memcmp(bf, "GNU", sizeof("GNU")) == 0) { - if (read(fd, build_id, - BUILD_ID_SIZE) == BUILD_ID_SIZE) { + size_t sz = min(descsz, size); + if (read(fd, build_id, sz) == (ssize_t)sz) { + memset(build_id + sz, 0, size - sz); err = 0; break; } - } else if (read(fd, bf, descsz) != descsz) + } else if (read(fd, bf, descsz) != (ssize_t)descsz) break; } else { int n = namesz + descsz; -- 2.20.1