tools/perf/util/build-id.c | 2 +- tools/perf/util/disasm.c | 4 +++- tools/perf/util/dso.c | 11 ++++++----- 3 files changed, 10 insertions(+), 7 deletions(-)
The flat symfs layout was implemented inside __symbol__join_symfs() alone,
which went from
return path__join(bf, size, symbol_conf.symfs, path);
to taking perf_basename(path) first. No caller was changed, so all of them
got it. Most pass dso__long_name(), which is what the option is about, but
some pass a path perf built itself:
dso.c "/usr/lib/debug" -> "debug"
dso.c "/usr/lib/debug/.build-id/" -> ""
build-id.c "/usr/lib/debug/.build-id/" -> ""
disasm.c <file under buildid_dir> -> last component
perf_basename() yields "" for a path ending in '/'. So with --symfs
DIR,flat the FEDORA, UBUNTU and MIXEDUP_UBUNTU debuginfo lookups land in
<symfs>/debug/, the two build-id ones in <symfs> itself, and disasm.c
flattens a path under perf's own build-id cache.
Use path__join() at those sites, which is what the helper did for them
before. A hierarchy layout is unaffected, being that same call. The
OPENEMBEDDED site passes "", where perf_basename() is already a no-op;
it is converted for uniformity. Every remaining __symbol__join_symfs()
caller passes a path from the profiled system.
Fixes: f182573e06ab ("perf tools: Add layout support for --symfs option")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
---
tools/perf/util/build-id.c | 2 +-
tools/perf/util/disasm.c | 4 +++-
tools/perf/util/dso.c | 11 ++++++-----
3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index eb95ab90f974..0c89fe75a650 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -599,7 +599,7 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
dirname = dirbuf;
}
- len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
+ len = path__join(debugfile, PATH_MAX, symbol_conf.symfs, dirname);
snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
sbuild_id + 2);
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 0a1a7e9cf3ef..decf9348d735 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -31,6 +31,7 @@
#include "map.h"
#include "maps.h"
#include "namespaces.h"
+#include "path.h"
#include "srcline.h"
#include "symbol.h"
#include "thread.h"
@@ -1173,7 +1174,8 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
build_id_filename = dso__build_id_filename(dso, NULL, 0, false);
if (build_id_filename) {
- __symbol__join_symfs(filename, filename_size, build_id_filename);
+ path__join(filename, filename_size, symbol_conf.symfs,
+ build_id_filename);
free(build_id_filename);
} else {
if (dso__has_build_id(dso))
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 2309196d8df3..314c9a0edf28 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -167,12 +167,12 @@ int dso__read_binary_type_filename(const struct dso *dso,
break;
case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
- len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+ len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
snprintf(filename + len, size - len, "%s.debug", dso__long_name(dso));
break;
case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
- len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+ len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
snprintf(filename + len, size - len, "%s", dso__long_name(dso));
break;
@@ -187,7 +187,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
ret = -1;
break;
}
- len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
+ len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
snprintf(filename + len, size - len, "%s", dso__long_name(dso) + 4);
break;
@@ -200,7 +200,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
while (last_slash != dso__long_name(dso) && *last_slash != '/')
last_slash--;
- len = __symbol__join_symfs(filename, size, "");
+ len = path__join(filename, size, symbol_conf.symfs, "");
dir_size = last_slash - dso__long_name(dso) + 2;
if (dir_size > (size - len)) {
ret = -1;
@@ -219,7 +219,8 @@ int dso__read_binary_type_filename(const struct dso *dso,
}
build_id__snprintf(dso__bid(dso), build_id_hex, sizeof(build_id_hex));
- len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
+ len = path__join(filename, size, symbol_conf.symfs,
+ "/usr/lib/debug/.build-id/");
snprintf(filename + len, size - len, "%.2s/%s.debug",
build_id_hex, build_id_hex + 2);
break;
--
2.43.0On Mon, Aug 10, 2026 at 10:00 PM Zhan Xusheng <zhanxusheng1024@gmail.com> wrote:
>
> The flat symfs layout was implemented inside __symbol__join_symfs() alone,
> which went from
>
> return path__join(bf, size, symbol_conf.symfs, path);
>
> to taking perf_basename(path) first. No caller was changed, so all of them
> got it. Most pass dso__long_name(), which is what the option is about, but
> some pass a path perf built itself:
>
> dso.c "/usr/lib/debug" -> "debug"
> dso.c "/usr/lib/debug/.build-id/" -> ""
> build-id.c "/usr/lib/debug/.build-id/" -> ""
> disasm.c <file under buildid_dir> -> last component
>
> perf_basename() yields "" for a path ending in '/'. So with --symfs
> DIR,flat the FEDORA, UBUNTU and MIXEDUP_UBUNTU debuginfo lookups land in
> <symfs>/debug/, the two build-id ones in <symfs> itself, and disasm.c
> flattens a path under perf's own build-id cache.
>
> Use path__join() at those sites, which is what the helper did for them
> before. A hierarchy layout is unaffected, being that same call. The
> OPENEMBEDDED site passes "", where perf_basename() is already a no-op;
> it is converted for uniformity. Every remaining __symbol__join_symfs()
> caller passes a path from the profiled system.
>
> Fixes: f182573e06ab ("perf tools: Add layout support for --symfs option")
> Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Thanks Zhan! Would it be possible to provide a before and after the
patch so we can better appreciate the issue you are fixing?
Thanks,
Ian
> ---
> tools/perf/util/build-id.c | 2 +-
> tools/perf/util/disasm.c | 4 +++-
> tools/perf/util/dso.c | 11 ++++++-----
> 3 files changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index eb95ab90f974..0c89fe75a650 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -599,7 +599,7 @@ static char *build_id_cache__find_debug(const char *sbuild_id,
> dirname = dirbuf;
> }
>
> - len = __symbol__join_symfs(debugfile, PATH_MAX, dirname);
> + len = path__join(debugfile, PATH_MAX, symbol_conf.symfs, dirname);
> snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
> sbuild_id + 2);
>
> diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> index 0a1a7e9cf3ef..decf9348d735 100644
> --- a/tools/perf/util/disasm.c
> +++ b/tools/perf/util/disasm.c
> @@ -31,6 +31,7 @@
> #include "map.h"
> #include "maps.h"
> #include "namespaces.h"
> +#include "path.h"
> #include "srcline.h"
> #include "symbol.h"
> #include "thread.h"
> @@ -1173,7 +1174,8 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
>
> build_id_filename = dso__build_id_filename(dso, NULL, 0, false);
> if (build_id_filename) {
> - __symbol__join_symfs(filename, filename_size, build_id_filename);
> + path__join(filename, filename_size, symbol_conf.symfs,
> + build_id_filename);
> free(build_id_filename);
> } else {
> if (dso__has_build_id(dso))
> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index 2309196d8df3..314c9a0edf28 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -167,12 +167,12 @@ int dso__read_binary_type_filename(const struct dso *dso,
> break;
>
> case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
> - len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
> + len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
> snprintf(filename + len, size - len, "%s.debug", dso__long_name(dso));
> break;
>
> case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
> - len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
> + len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
> snprintf(filename + len, size - len, "%s", dso__long_name(dso));
> break;
>
> @@ -187,7 +187,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
> ret = -1;
> break;
> }
> - len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
> + len = path__join(filename, size, symbol_conf.symfs, "/usr/lib/debug");
> snprintf(filename + len, size - len, "%s", dso__long_name(dso) + 4);
> break;
>
> @@ -200,7 +200,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
> while (last_slash != dso__long_name(dso) && *last_slash != '/')
> last_slash--;
>
> - len = __symbol__join_symfs(filename, size, "");
> + len = path__join(filename, size, symbol_conf.symfs, "");
> dir_size = last_slash - dso__long_name(dso) + 2;
> if (dir_size > (size - len)) {
> ret = -1;
> @@ -219,7 +219,8 @@ int dso__read_binary_type_filename(const struct dso *dso,
> }
>
> build_id__snprintf(dso__bid(dso), build_id_hex, sizeof(build_id_hex));
> - len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
> + len = path__join(filename, size, symbol_conf.symfs,
> + "/usr/lib/debug/.build-id/");
> snprintf(filename + len, size - len, "%.2s/%s.debug",
> build_id_hex, build_id_hex + 2);
> break;
> --
> 2.43.0
>
On Mon, 17 Aug 2026 14:42:26 -0700, Ian Rogers wrote:
> Would it be possible to provide a before and after the
> patch so we can better appreciate the issue you are fixing?
Two builds of 8d3ae59288f1 differing only by the patch, empty /tmp/s:
perf record -o pd.data -- sleep 0.3
strace -f -e trace=openat,newfstatat \
perf report -i pd.data --symfs /tmp/s,flat --stdio
15 paths get tried under /tmp/s. Four of them differ. Before:
/tmp/s/debug/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/tmp/s/debug/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/tmp/s/debug/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2.debug
/tmp/s/f5/8808c9c8a388055b126492a1706d732761f86e.debug
After:
/tmp/s//usr/lib/debug/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/tmp/s//usr/lib/debug/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
/tmp/s//usr/lib/debug/usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2.debug
/tmp/s//usr/lib/debug/.build-id/f5/8808c9c8a388055b126492a1706d732761f86e.debug
The first three are FEDORA, UBUNTU and MIXEDUP_UBUNTU, the fourth
BUILDID_DEBUGINFO. What the old ones have in common is the shape: the
prefix perf supplied is flattened while dso__long_name() is still appended
whole, so they follow neither 'flat' nor 'hierarchy'.
Among the 11 unchanged paths are the basename lookups the option exists
for, so it keeps working:
/tmp/s/ld-linux-x86-64.so.2
/tmp/s/sleep
/tmp/s/vmlinux
The same trace with ,hierarchy is identical between the two builds. The
doubled slash is path__join() on a component starting with '/', present
without the patch too, in 7 of the 15.
I will add this to the changelog in v2.
Thanks,
Zhan Xusheng
© 2016 - 2026 Red Hat, Inc.