From 1a5f9334a45a6b0c1cd7341cc72a3b87adad1d27 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Sat, 13 Jun 2026 15:55:33 -0300 Subject: [PATCH] perf dso: Set standard errno on decompression failure dso__get_filename() sets errno to a negative custom DSO_LOAD_ERRNO value when kernel module decompression fails: errno = *dso__load_errno(dso); /* e.g. -9996 */ The caller __open_dso() then computes fd = -errno, producing a large positive value (9996) that looks like a valid file descriptor. This can cause close_data_fd() to close an unrelated fd used by another subsystem. Set errno to EIO instead. The detailed error code is already stored in dso__load_errno(dso) for diagnostic messages. Fixes: 1d6b3c9ba756a513 ("perf tools: Decompress kernel module when reading DSO data") Reported-by: sashiko-bot Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/dso.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index 79f1a30f3683..2309196d8df3 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -600,7 +600,13 @@ static char *dso__get_filename(struct dso *dso, const char *root_dir, size_t len = sizeof(newpath); if (dso__decompress_kmodule_path(dso, name, newpath, len) < 0) { - errno = *dso__load_errno(dso); + /* + * Use a standard errno value, not the negative custom + * DSO_LOAD_ERRNO stored in dso__load_errno(dso): + * __open_dso() computes fd = -errno, so a negative + * errno produces a positive fd that looks valid. + */ + errno = EIO; goto out; }