From 915eed20e40f4dcb142cb29a3de6f6ba67f4bb5a Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Sat, 21 May 2016 17:46:10 +0200 Subject: um: Support kcov This adds support for kcov to UML. There is a small problem where UML will randomly segfault during boot; this is because current_thread_info() occasionally returns an invalid (non-NULL) pointer and we try to dereference it in __sanitizer_cov_trace_pc(). I consider this a bug in UML itself and this patch merely exposes it. [v2: disable instrumentation in UML-specific code] Cc: Quentin Casasnovas Cc: Richard Weinberger Cc: Thomas Meyer Cc: user-mode-linux-devel Cc: Dmitry Vyukov Signed-off-by: Vegard Nossum Signed-off-by: Richard Weinberger diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common index 08d931c..f8530d8 100644 --- a/arch/um/Kconfig.common +++ b/arch/um/Kconfig.common @@ -1,6 +1,7 @@ config UML bool default y + select ARCH_HAS_KCOV select HAVE_ARCH_AUDITSYSCALL select HAVE_ARCH_SECCOMP_FILTER select HAVE_UID16 diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile index a6a5e42..2f36d51 100644 --- a/arch/um/kernel/Makefile +++ b/arch/um/kernel/Makefile @@ -3,6 +3,11 @@ # Licensed under the GPL # +# Don't instrument UML-specific code; without this, we may crash when +# accessing the instrumentation buffer for the first time from the +# kernel. +KCOV_INSTRUMENT := n + CPPFLAGS_vmlinux.lds := -DSTART=$(LDS_START) \ -DELF_ARCH=$(LDS_ELF_ARCH) \ -DELF_FORMAT=$(LDS_ELF_FORMAT) \ diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile index 08ff509..ada473b 100644 --- a/arch/um/os-Linux/Makefile +++ b/arch/um/os-Linux/Makefile @@ -3,6 +3,9 @@ # Licensed under the GPL # +# Don't instrument UML-specific code +KCOV_INSTRUMENT := n + obj-y = aio.o execvp.o file.o helper.o irq.o main.o mem.o process.o \ registers.o sigio.o signal.o start_up.o time.o tty.o \ umid.o user_syms.o util.o drivers/ skas/ diff --git a/arch/x86/um/vdso/Makefile b/arch/x86/um/vdso/Makefile index 6c803ca..d72dec4 100644 --- a/arch/x86/um/vdso/Makefile +++ b/arch/x86/um/vdso/Makefile @@ -2,6 +2,9 @@ # Building vDSO images for x86. # +# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. +KCOV_INSTRUMENT := n + VDSO64-y := y vdso-install-$(VDSO64-y) += vdso.so -- cgit v0.10.2