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[83.244.142.114]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a0017652d1sm144207825e9.5.2026.09.27.18.02.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Sep 2026 18:02:38 -0700 (PDT) From: Michal Pluta To: acme@kernel.org, namhyung@kernel.org Cc: Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/5] perf symbol: Don't return an unterminated Rust demangle buffer Date: Mon, 28 Sep 2026 02:02:24 +0100 Message-ID: <20260928010227.1903673-3-michalpl2003@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260928010227.1903673-1-michalpl2003@gmail.com> References: <20260928010227.1903673-1-michalpl2003@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When dso__demangle_sym() runs out of retries or fails to grow the output buffer for a Rust v0 symbol, it returns the buffer and callers blindly use it as the demangled symbol name. However, rust_demangle_display_demangle() doesn't NUL terminate its output when it reports OverflowOverflow, so the buffer isn't a string. Free the buffer and return NULL in both cases. Callers already fall back to the mangled name when no demangled name is returned. Fixes: e20848c317b5 ("perf symbol-elf: Integrate rust-v0 demangling") Assisted-by: LLM Signed-off-by: Michal Pluta --- tools/perf/util/symbol.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 163652f071c6..3cb42805a82f 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -2762,17 +2762,16 @@ char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name) buf_len < 1024 * 1024; buf_len += 32) { char *tmp = realloc(demangled, buf_len); - if (!tmp) { - /* Failure to grow output buffer, return what is there. */ - return demangled; - } + if (!tmp) + break; demangled = tmp; if (rust_demangle_display_demangle(&rust_demangle, demangled, buf_len, /*alternate=*/true) == OverflowOk) return demangled; } - /* Buffer exceeded sensible bounds, return what is there. */ - return demangled; + /* Failure to grow output buffer or buffer exceeded sensible bounds. */ + free(demangled); + return NULL; } demangled = cxx_demangle_sym(elf_name, verbose > 0, verbose > 0); -- 2.43.0