From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DED5022618F for ; Thu, 1 May 2025 12:16:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746101798; cv=none; b=P1mHs/6kNYUgG0ViuDUCGssjyK0LOYJVvC6MYtQ1ShS4JdCl+y5RtCFIVL2yTi2SOIsE45CRPN2dgbIwkw2ouc9bek12NviIeYrIwdrMkbfMIw4E8qlg4suVbtIY0UbsdMeAu4RJkHePFZ8Wc7cNt7mSEncP3ujuczj7FfWoqoY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746101798; c=relaxed/simple; bh=IyknQ/1KxQ4jy7cl/9HHS98hqktVwXtxDa2ScsUKzik=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=SAoIF6VTJMsRjOjf973BfUZmG6urfbwviaErOt25mEAwLxEKW8l5X01k1+ym9/jBzUFXyrTKWDuxK2CJxTPzpYNmm+eOR3emV2/Z7KM1+y7k0czAdX6XB5Sy7niqFPdzr0pdo/3hp0f6kKjyuxg2aVl28D+JGrEsdGzwwK24Qxg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=SBOWmZyy; arc=none smtp.client-ip=209.85.208.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SBOWmZyy" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-5f4d2e9cdbdso650003a12.1 for ; Thu, 01 May 2025 05:16:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1746101795; x=1746706595; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=/0A3i0y7AEXGrVw5WCxmIfPgVwLI2iY2Vm/Il51dpo4=; b=SBOWmZyyaOrGXV/KZAEgc+Pl9sELwGS56PevUJfcPjfrw+VD8jcdu4bphQPoGipedh bmDmR74jnByecSA1wg1sR6ER74cFqlu+MrhSWaA3xISnWTdnQ84iMu8lPMyFxF/bi1rd v23aKVypdpCVVMzcbTCCCkph+mN1Ph7kCSgKiaci2jJD3tLdoVBnYEfEenFB+lPMNlWL MReK2Xb4OzzwtOUoQw4GJdZFhmiymlv9q4LS19awWK8a9KxaUBmhUuSDBMEyYl3RMGhf sW2iJtKKUc9L+TnQykN0a6fJzWsRLmwx/cf7fr8ZgVQknGAVwakfxZlg69qs8jhAR029 UTaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746101795; x=1746706595; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=/0A3i0y7AEXGrVw5WCxmIfPgVwLI2iY2Vm/Il51dpo4=; b=gZnlxeF2arL6FTVJ6YQrAEuLDwBeC0EfvIpuMtPkBb36qAzeniriSWGpWdBHs9md9G AS9WoilyjwdfkHMSH/cbJzLd/PDEhdvEXPSq4dNca4sJfaj06cyoPdmO+TChL0xQ0bur b9ONabBZmnYimdrhzCJdcuyDqOSGT3a/b1isvE67c1/h2JE1GbPyfHKjnJT6WHhoJ5ZO KUpiQH2W+BBEQOpCGQGFx7NVKfI2mQqi7JKs0Q7fNZbGuB2Ub9CFPojYsMXKAiRieouu zc085iwuz3OhJSGiXq/6PoGVPEy9pw2wlaG/yR4VQWXwm0VHrXzdcAiubH7EyVikeSvV P1jg== X-Forwarded-Encrypted: i=1; AJvYcCWd7njwDXDuy3fxlk6vXsADJauwLgTK/ekmaOakA0W5OfCft4K0xmPwxVArxkIjk7Q9RgBs5c57Njn+kNQ=@vger.kernel.org X-Gm-Message-State: AOJu0YwDtsdMmMS3SxRofmOVo7dRqPQUwm1AdbiQNTL6DSLkOgb+W8ro ZcnZzkTUR6YGXuVorAxgbnXv9816JLc0k+ZpL9hTMstH8+8TLAfyjJ7o/ly9xKzPATIQ9b8aFPc BJZyWq4WzmDprmg== X-Google-Smtp-Source: AGHT+IHPX/PFUHy/B5MO7ne7F95HMGksgkzZCkh09JGriq4Dil8oYGmEhlEKL/ontfKDHtVmoGpFcCN9QJjYhiI= X-Received: from edi23.prod.google.com ([2002:a05:6402:3057:b0:5f8:f539:d6d4]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:3549:b0:5f7:eafe:76d5 with SMTP id 4fb4d7f45d1cf-5f89ae69fdbmr5712393a12.8.1746101795323; Thu, 01 May 2025 05:16:35 -0700 (PDT) Date: Thu, 01 May 2025 12:16:16 +0000 Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAA9mE2gC/23MQQ7CIBCF4as0sxbDIG2tK+9huqh0oETtGKhE0 3B3sWuX/8vLt0Kk4CnCqVohUPLR81xC7Sow0zA7En4sDUqqWuqDFOEVF3EznERjWm1HadHKBsr /Gcj692Zd+tKTjwuHz0Yn/K3/lIQCxbUbqNOoj9jWZ8fs7rQ3/IA+5/wF2Ne1B6MAAAA= X-Change-Id: 20250430-rust-kcov-6c74fd0f1f06 X-Developer-Key: i=aliceryhl@google.com; a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=3372; i=aliceryhl@google.com; h=from:subject:message-id; bh=IyknQ/1KxQ4jy7cl/9HHS98hqktVwXtxDa2ScsUKzik=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBoE2Yc1seMwVTR5LqQgHftFKn3mcU9oBGoTAYMA XywZQOUJWaJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCaBNmHAAKCRAEWL7uWMY5 RruED/41KjyEBSNGnCAlbC4pSd6vvUYRCa5IqugILNA8EWWtm5XV9HG03IkpVx9l+WPGCL4raW7 bT2QtGi8GeAZbwMap6yw8UgVvZiY28Lij+WpnY2OVdsJF/K2HbjEdk4JEHNYj2C9+i+ASxTwG69 A/X717LIJcJ4EXFsfO3TVIafKmpqbCgonlQuaio5BGKsE1UzRW0+SpM6s7LTkNi6aNu/9wmKpnb 8tq+mESF2tJgKjOiFddb2iHUR3Rx3lR4XQYNN38JC73fjMfW7t6CPEsLwQscoS/3u60zajicOS5 lZQoWisQNarEmFfngt6PDpK91WJJDjrIHWH0KPdiJ2FHWjVP1XTXY4d5nBgk9NCOl39TmerwCYW M59Id7N74zcvrA6sVIrOGB73JiWdYpZcnCxYBH3kvTTErHZvtqM7KMBPl5WWhbimVOnY1WYMXv+ 6bg/rZjLhQwVgsdVcjUEKk901szchGmin0XreBHwnx9KZEGkCtW8+rfROMpkliIP1HLl/dMTxAN drQr4WXpIrbkME5OIUtsW03u3HqG4iW1x9cmNXhtQb44r0TDoEKS23in3hEfqarJ/he4hxMhumA WtZWUY5kI7tm+uZaFe1e2preFMcwNYTTbkTcobH0Yuv1OdUEtfltjYFn69OMriD0xJc3aVcMnYi HWr3YoEPbjHxiNQ== X-Mailer: b4 0.14.2 Message-ID: <20250501-rust-kcov-v2-1-b71e83e9779f@google.com> Subject: [PATCH v2] kcov: rust: add flags for KCOV with Rust From: Alice Ryhl To: Dmitry Vyukov , Andrey Konovalov , Masahiro Yamada , Nathan Chancellor , Miguel Ojeda Cc: Nicolas Schier , Boqun Feng , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Andreas Hindborg , Trevor Gross , Danilo Krummrich , Aleksandr Nogikh , Nick Desaulniers , Bill Wendling , Justin Stitt , kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, llvm@lists.linux.dev, Matthew Maurer , Alexander Potapenko , Alice Ryhl Content-Type: text/plain; charset="utf-8" Rust code is currently not instrumented properly when KCOV is enabled. Thus, add the relevant flags to perform instrumentation correctly. This is necessary for efficient fuzzing of Rust code. The sanitizer-coverage features of LLVM have existed for long enough that they are available on any LLVM version supported by rustc, so we do not need any Kconfig feature detection. The coverage level is set to 3, as that is the level needed by trace-pc. We do not instrument `core` since when we fuzz the kernel, we are looking for bugs in the kernel, not the Rust stdlib. Co-developed-by: Matthew Maurer Signed-off-by: Matthew Maurer Reviewed-by: Alexander Potapenko Signed-off-by: Alice Ryhl --- I did not pick up the Tested-by due to the changes. I verified that it looks right under objdump, but I don't have a syzkaller setup I can try it with. --- Changes in v2: - Ignore `core` in KCOV. - Link to v1: https://lore.kernel.org/r/20250430-rust-kcov-v1-1-b9ae94148175@google.com --- rust/Makefile | 1 + scripts/Makefile.kcov | 6 ++++++ scripts/Makefile.lib | 3 +++ 3 files changed, 10 insertions(+) diff --git a/rust/Makefile b/rust/Makefile index 3aca903a7d08cfbf4d4e0f172dab66e9115001e3..80c84749d734842774a3ac2aabbc944a68d02484 100644 --- a/rust/Makefile +++ b/rust/Makefile @@ -492,6 +492,7 @@ $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs \ ifneq ($(or $(CONFIG_X86_64),$(CONFIG_X86_32)),) $(obj)/core.o: scripts/target.json endif +KCOV_INSTRUMENT_core.o := n $(obj)/compiler_builtins.o: private skip_gendwarfksyms = 1 $(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*' diff --git a/scripts/Makefile.kcov b/scripts/Makefile.kcov index 67e8cfe3474b7dcf7552e675cffe356788e6c3a2..ddcc3c6dc513e1988aeaf07b8efa106e8dffa640 100644 --- a/scripts/Makefile.kcov +++ b/scripts/Makefile.kcov @@ -3,4 +3,10 @@ kcov-flags-$(CONFIG_CC_HAS_SANCOV_TRACE_PC) += -fsanitize-coverage=trace-pc kcov-flags-$(CONFIG_KCOV_ENABLE_COMPARISONS) += -fsanitize-coverage=trace-cmp kcov-flags-$(CONFIG_GCC_PLUGIN_SANCOV) += -fplugin=$(objtree)/scripts/gcc-plugins/sancov_plugin.so +kcov-rflags-y += -Cpasses=sancov-module +kcov-rflags-y += -Cllvm-args=-sanitizer-coverage-level=3 +kcov-rflags-y += -Cllvm-args=-sanitizer-coverage-trace-pc +kcov-rflags-$(CONFIG_KCOV_ENABLE_COMPARISONS) += -Cllvm-args=-sanitizer-coverage-trace-compares + export CFLAGS_KCOV := $(kcov-flags-y) +export RUSTFLAGS_KCOV := $(kcov-rflags-y) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 2fe73cda0bddb9dcf709d0a9ae541318d54754d2..520905f19a9b19631394cfb5e129effb8846d5b8 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -169,6 +169,9 @@ ifeq ($(CONFIG_KCOV),y) _c_flags += $(if $(patsubst n%,, \ $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \ $(CFLAGS_KCOV)) +_rust_flags += $(if $(patsubst n%,, \ + $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \ + $(RUSTFLAGS_KCOV)) endif # --- base-commit: 9c32cda43eb78f78c73aee4aa344b777714e259b change-id: 20250430-rust-kcov-6c74fd0f1f06 Best regards, -- Alice Ryhl