s390/vdso: filter out -mstack-guard and -mstack-size

When CONFIG_VMAP_STACK is disabled, the user can enable CONFIG_STACK_CHECK,
which adds a stack overflow check to each C function in the kernel. This is
also done for functions in the vdso page. These functions are run in user
context and user stack sizes are usually different to what the kernel uses.
This might trigger the stack check although the stack size is valid.
Therefore filter the -mstack-guard and -mstack-size flags when compiling
vdso C files.

Cc: stable@kernel.org # 5.10+
Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 69c45f6..609e369 100644 (file)
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -77,10 +77,12 @@ KBUILD_AFLAGS_DECOMPRESSOR += $(aflags-y)
 KBUILD_CFLAGS_DECOMPRESSOR += $(cflags-y)
 
 ifneq ($(call cc-option,-mstack-size=8192 -mstack-guard=128),)
-cflags-$(CONFIG_CHECK_STACK) += -mstack-size=$(STACK_SIZE)
-ifeq ($(call cc-option,-mstack-size=8192),)
-cflags-$(CONFIG_CHECK_STACK) += -mstack-guard=$(CONFIG_STACK_GUARD)
-endif
+  CC_FLAGS_CHECK_STACK := -mstack-size=$(STACK_SIZE)
+  ifeq ($(call cc-option,-mstack-size=8192),)
+    CC_FLAGS_CHECK_STACK += -mstack-guard=$(CONFIG_STACK_GUARD)
+  endif
+  export CC_FLAGS_CHECK_STACK
+  cflags-$(CONFIG_CHECK_STACK) += $(CC_FLAGS_CHECK_STACK)
 endif
 
 ifdef CONFIG_EXPOLINE

diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index e7d9117..9e2b95a 100644 (file)
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -8,8 +8,9 @@ ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT
 include $(srctree)/lib/vdso/Makefile
 obj-vdso64 = vdso_user_wrapper.o note.o
 obj-cvdso64 = vdso64_generic.o getcpu.o
-CFLAGS_REMOVE_getcpu.o = -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE)
-CFLAGS_REMOVE_vdso64_generic.o = -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE)
+VDSO_CFLAGS_REMOVE := -pg $(CC_FLAGS_FTRACE) $(CC_FLAGS_EXPOLINE) $(CC_FLAGS_CHECK_STACK)
+CFLAGS_REMOVE_getcpu.o = $(VDSO_CFLAGS_REMOVE)
+CFLAGS_REMOVE_vdso64_generic.o = $(VDSO_CFLAGS_REMOVE)
 
 # Build rules