um: Support kcov (915eed20) · Commits · 戴 / test

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 <quentin.casasnovas@oracle.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: user-mode-linux-devel <user-mode-linux-devel@lists.sourceforge.net> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by:

Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by:

Richard Weinberger <richard@nod.at>

arch/um/Kconfig.common

+1 −0

Original line number	Diff line number	Diff line
		config UML
		bool
		default y
		select ARCH_HAS_KCOV
		select HAVE_ARCH_AUDITSYSCALL
		select HAVE_ARCH_SECCOMP_FILTER
		select HAVE_UID16

arch/um/kernel/Makefile

+5 −0

Original line number	Diff line number	Diff line
		@@ -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) \

arch/um/os-Linux/Makefile

+3 −0

Original line number	Diff line number	Diff line
		@@ -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/

arch/x86/um/vdso/Makefile

+3 −0

Original line number	Diff line number	Diff line
		@@ -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

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