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AJvYcCXTmIDjTe9bQqrw4zM9KQMZKIl1daQqzJDgIN8UZ6jNYvmSSn+YaeyNQ19wg3qNWx24NzEVx5bHvJPHQec=@vger.kernel.org X-Gm-Message-State: AOJu0YzsSJa8uKOE39VaFUv4+AN3HD6ZTjmx25LbFbBX9D1fWooXvAb6 YPQucOotsWfq106G3KUsu6LLlysuTLAr4YnrXBgaw3DjGVUZFd5Zsn5CXzcwGSFY2g7L/TPqy3G 9DJWYDg== X-Google-Smtp-Source: AGHT+IHpZ5VlJorp1XLdO4xxLYlKlSsb2LC7QkiWpuKlb/RDNKu1odUVhKBJq6tTFUk49mJkrqOta4tjDK4= X-Received: from wrbfy8.prod.google.com ([2002:a05:6000:2d88:b0:3b7:8d84:e97]) (user=glider job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:3101:b0:3a4:dfc2:bb60 with SMTP id ffacd0b85a97d-3b794fd3f6cmr5156251f8f.26.1753962706607; Thu, 31 Jul 2025 04:51:46 -0700 (PDT) Date: Thu, 31 Jul 2025 13:51:30 +0200 In-Reply-To: <20250731115139.3035888-1-glider@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250731115139.3035888-1-glider@google.com> X-Mailer: git-send-email 2.50.1.552.g942d659e1b-goog Message-ID: <20250731115139.3035888-2-glider@google.com> Subject: [PATCH v4 01/10] x86: kcov: disable instrumentation of arch/x86/kernel/tsc.c From: Alexander Potapenko To: glider@google.com Cc: quic_jiangenj@quicinc.com, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Aleksandr Nogikh , Andrey Konovalov , Borislav Petkov , Dave Hansen , Dmitry Vyukov , Ingo Molnar , Josh Poimboeuf , Marco Elver , Peter Zijlstra , Thomas Gleixner Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" sched_clock() appears to be called from interrupts, producing spurious coverage, as reported by CONFIG_KCOV_SELFTEST: RIP: 0010:__sanitizer_cov_trace_pc_guard+0x66/0xe0 kernel/kcov.c:288 ... fault_in_kernel_space+0x17/0x70 arch/x86/mm/fault.c:1119 handle_page_fault arch/x86/mm/fault.c:1477 exc_page_fault+0x56/0x110 arch/x86/mm/fault.c:1538 asm_exc_page_fault+0x26/0x30 ./arch/x86/include/asm/idtentry.h:623 RIP: 0010:__sanitizer_cov_trace_pc_guard+0x66/0xe0 kernel/kcov.c:288 ... sched_clock+0x12/0x70 arch/x86/kernel/tsc.c:284 __lock_pin_lock kernel/locking/lockdep.c:5628 lock_pin_lock+0xd7/0x180 kernel/locking/lockdep.c:5959 rq_pin_lock kernel/sched/sched.h:1761 rq_lock kernel/sched/sched.h:1838 __schedule+0x3a8/0x4b70 kernel/sched/core.c:6691 preempt_schedule_irq+0xbf/0x160 kernel/sched/core.c:7090 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 ./arch/x86/include/asm/idtentry.h:707 RIP: 0010:selftest+0x26/0x60 kernel/kcov.c:1223 ... kcov_init+0x81/0xa0 kernel/kcov.c:1252 do_one_initcall+0x2e1/0x910 do_initcall_level+0xff/0x160 init/main.c:1319 do_initcalls+0x4a/0xa0 init/main.c:1335 kernel_init_freeable+0x448/0x610 init/main.c:1567 kernel_init+0x24/0x230 init/main.c:1457 ret_from_fork+0x60/0x90 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Signed-off-by: Alexander Potapenko --- Change-Id: Ica191d73bf5601b31e893d6e517b91be983e986a --- arch/x86/kernel/Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 0d2a6d953be91..ca134ce03eea9 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -43,6 +43,8 @@ KCOV_INSTRUMENT_dumpstack_$(BITS).o :=3D n KCOV_INSTRUMENT_unwind_orc.o :=3D n KCOV_INSTRUMENT_unwind_frame.o :=3D n KCOV_INSTRUMENT_unwind_guess.o :=3D n +# Avoid instrumenting code that produces spurious coverage in interrupts. +KCOV_INSTRUMENT_tsc.o :=3D n =20 CFLAGS_head32.o :=3D -fno-stack-protector CFLAGS_head64.o :=3D -fno-stack-protector --=20 2.50.1.552.g942d659e1b-goog