* [PATCH v1] perf symbol: Fix ENOENT case for filename__read_build_id
@ 2025-12-07 2:23 Ian Rogers
2025-12-09 9:47 ` James Clark
0 siblings, 1 reply; 2+ messages in thread
From: Ian Rogers @ 2025-12-07 2:23 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Alexander Shishkin, Jiri Olsa, Ian Rogers,
Adrian Hunter, James Clark, Stephen Brennan, Haibo Xu,
linux-perf-users, linux-kernel
Some callers of filename__read_build_id assume the error value must be
-1, fix by making them handle all < 0 values.
If is_regular_file fails in filename__read_build_id then it could be
the file is missing (ENOENT) and it would be wrong to return
-EWOULDBLOCK in that case. Fix the logic so -EWOULDBLOCK is only
reported if other errors with stat haven't occurred.
Fixes: 834ebb5678d7 ("perf tools: Don't read build-ids from non-regular files")
Signed-off-by: Ian Rogers <irogers@google.com>
---
Note, a shorter version of this patch appeared in a series
cleaning/refactoring the build id reading code:
https://lore.kernel.org/lkml/20251201205509.195451-11-irogers@google.com/
It is sent without the refactor for the sake of fixing the bug in an
earlier release.
---
tools/perf/builtin-buildid-cache.c | 6 ++++--
tools/perf/util/libbfd.c | 4 +++-
tools/perf/util/symbol-elf.c | 4 +++-
tools/perf/util/symbol-minimal.c | 4 +++-
4 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index c98104481c8a..539e779e3268 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -276,12 +276,14 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
{
char filename[PATH_MAX];
struct build_id bid = { .size = 0, };
+ int err;
if (!dso__build_id_filename(dso, filename, sizeof(filename), false))
return true;
- if (filename__read_build_id(filename, &bid) == -1) {
- if (errno == ENOENT)
+ err = filename__read_build_id(filename, &bid);
+ if (err < 0) {
+ if (err == -ENOENT)
return false;
pr_warning("Problems with %s file, consider removing it from the cache\n",
diff --git a/tools/perf/util/libbfd.c b/tools/perf/util/libbfd.c
index 0099b415decc..edf0829e9635 100644
--- a/tools/perf/util/libbfd.c
+++ b/tools/perf/util/libbfd.c
@@ -391,8 +391,10 @@ int libbfd__read_build_id(const char *filename, struct build_id *bid)
if (!filename)
return -EFAULT;
+
+ errno = 0;
if (!is_regular_file(filename))
- return -EWOULDBLOCK;
+ return errno == 0 ? -EWOULDBLOCK : -errno;
fd = open(filename, O_RDONLY);
if (fd < 0)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 957143fbf8a0..d1dcafa4b3b8 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -902,8 +902,10 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
if (!filename)
return -EFAULT;
+
+ errno = 0;
if (!is_regular_file(filename))
- return -EWOULDBLOCK;
+ return errno == 0 ? -EWOULDBLOCK : -errno;
err = kmod_path__parse(&m, filename);
if (err)
diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
index c6b17c14a2e9..8221dc9868f7 100644
--- a/tools/perf/util/symbol-minimal.c
+++ b/tools/perf/util/symbol-minimal.c
@@ -104,8 +104,10 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
if (!filename)
return -EFAULT;
+
+ errno = 0;
if (!is_regular_file(filename))
- return -EWOULDBLOCK;
+ return errno == 0 ? -EWOULDBLOCK : -errno;
fd = open(filename, O_RDONLY);
if (fd < 0)
--
2.52.0.223.gf5cc29aaa4-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] perf symbol: Fix ENOENT case for filename__read_build_id
2025-12-07 2:23 [PATCH v1] perf symbol: Fix ENOENT case for filename__read_build_id Ian Rogers
@ 2025-12-09 9:47 ` James Clark
0 siblings, 0 replies; 2+ messages in thread
From: James Clark @ 2025-12-09 9:47 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Alexander Shishkin, Jiri Olsa, Adrian Hunter,
Stephen Brennan, Haibo Xu, linux-perf-users, linux-kernel
On 07/12/2025 2:23 am, Ian Rogers wrote:
> Some callers of filename__read_build_id assume the error value must be
> -1, fix by making them handle all < 0 values.
>
> If is_regular_file fails in filename__read_build_id then it could be
> the file is missing (ENOENT) and it would be wrong to return
> -EWOULDBLOCK in that case. Fix the logic so -EWOULDBLOCK is only
> reported if other errors with stat haven't occurred.
>
> Fixes: 834ebb5678d7 ("perf tools: Don't read build-ids from non-regular files")
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> Note, a shorter version of this patch appeared in a series
> cleaning/refactoring the build id reading code:
> https://lore.kernel.org/lkml/20251201205509.195451-11-irogers@google.com/
> It is sent without the refactor for the sake of fixing the bug in an
> earlier release.
Reviewed-by: James Clark <james.clark@linaro.org>
> ---
> tools/perf/builtin-buildid-cache.c | 6 ++++--
> tools/perf/util/libbfd.c | 4 +++-
> tools/perf/util/symbol-elf.c | 4 +++-
> tools/perf/util/symbol-minimal.c | 4 +++-
> 4 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
> index c98104481c8a..539e779e3268 100644
> --- a/tools/perf/builtin-buildid-cache.c
> +++ b/tools/perf/builtin-buildid-cache.c
> @@ -276,12 +276,14 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
> {
> char filename[PATH_MAX];
> struct build_id bid = { .size = 0, };
> + int err;
>
> if (!dso__build_id_filename(dso, filename, sizeof(filename), false))
> return true;
>
> - if (filename__read_build_id(filename, &bid) == -1) {
> - if (errno == ENOENT)
> + err = filename__read_build_id(filename, &bid);
> + if (err < 0) {
> + if (err == -ENOENT)
> return false;
>
> pr_warning("Problems with %s file, consider removing it from the cache\n",
> diff --git a/tools/perf/util/libbfd.c b/tools/perf/util/libbfd.c
> index 0099b415decc..edf0829e9635 100644
> --- a/tools/perf/util/libbfd.c
> +++ b/tools/perf/util/libbfd.c
> @@ -391,8 +391,10 @@ int libbfd__read_build_id(const char *filename, struct build_id *bid)
>
> if (!filename)
> return -EFAULT;
> +
> + errno = 0;
> if (!is_regular_file(filename))
> - return -EWOULDBLOCK;
> + return errno == 0 ? -EWOULDBLOCK : -errno;
>
> fd = open(filename, O_RDONLY);
> if (fd < 0)
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 957143fbf8a0..d1dcafa4b3b8 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -902,8 +902,10 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
>
> if (!filename)
> return -EFAULT;
> +
> + errno = 0;
> if (!is_regular_file(filename))
> - return -EWOULDBLOCK;
> + return errno == 0 ? -EWOULDBLOCK : -errno;
>
> err = kmod_path__parse(&m, filename);
> if (err)
> diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c
> index c6b17c14a2e9..8221dc9868f7 100644
> --- a/tools/perf/util/symbol-minimal.c
> +++ b/tools/perf/util/symbol-minimal.c
> @@ -104,8 +104,10 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
>
> if (!filename)
> return -EFAULT;
> +
> + errno = 0;
> if (!is_regular_file(filename))
> - return -EWOULDBLOCK;
> + return errno == 0 ? -EWOULDBLOCK : -errno;
>
> fd = open(filename, O_RDONLY);
> if (fd < 0)
^ permalink raw reply [flat|nested] 2+ messages in thread
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