3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon <will.deacon@xxxxxxx> commit 6f1a6ae87c0c60d7c462ef8fd071f291aa7a9abb upstream. When building the kernel with a bare-metal (ELF) toolchain, the -shared option may not be passed down to collect2, resulting in silent corruption of the vDSO image (in particular, the DYNAMIC section is omitted). The effect of this corruption is that the dynamic linker fails to find the vDSO symbols and libc is instead used for the syscalls that we intended to optimise (e.g. gettimeofday). Functionally, there is no issue as the sigreturn trampoline is still intact and located by the kernel. This patch fixes the problem by explicitly passing -shared to the linker when building the vDSO. Reported-by: Szabolcs Nagy <Szabolcs.Nagy@xxxxxxx> Reported-by: James Greenlaigh <james.greenhalgh@xxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/kernel/vdso/Makefile | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -15,6 +15,10 @@ ccflags-y := -shared -fno-common -fno-bu ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) +# Workaround for bare-metal (ELF) toolchains that neglect to pass -shared +# down to collect2, resulting in silent corruption of the vDSO image. +ccflags-y += -Wl,-shared + obj-y += vdso.o extra-y += vdso.lds vdso-offsets.h CPPFLAGS_vdso.lds += -P -C -U$(ARCH) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html