Originally, bpfilter_umh was linked with -static only when
CONFIG_BPFILTER_UMH=y.
Commit 8a2cc0505cc4 ("bpfilter: use 'userprogs' syntax to build
bpfilter_umh") silently, accidentally dropped the CONFIG_BPFILTER_UMH=y
test in the Makefile. Revive it in order to link it dynamically when
CONFIG_BPFILTER_UMH=m.
Since commit b1183b6dca3e ("bpfilter: check if $(CC) can link static
libc in Kconfig"), the compiler must be capable of static linking to
enable CONFIG_BPFILTER_UMH, but it requires more than needed.
To loosen the compiler requirement, I changed the dependency as follows:
depends on CC_CAN_LINK
depends on m || CC_CAN_LINK_STATIC
If CONFIG_CC_CAN_LINK_STATIC in unset, CONFIG_BPFILTER_UMH is restricted
to 'm' or 'n'.
In theory, CONFIG_CC_CAN_LINK is not required for CONFIG_BPFILTER_UMH=y,
but I did not come up with a good way to describe it.
Fixes: 8a2cc0505cc4 ("bpfilter: use 'userprogs' syntax to build bpfilter_umh")
Reported-by: Michal Kubecek <mkube...@suse.cz>
Signed-off-by: Masahiro Yamada <masahi...@kernel.org>
---
net/bpfilter/Kconfig | 10 ++++++----
net/bpfilter/Makefile | 2 ++
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
index 84015ef3ee27..73d0b12789f1 100644
--- a/net/bpfilter/Kconfig
+++ b/net/bpfilter/Kconfig
@@ -9,12 +9,14 @@ menuconfig BPFILTER
if BPFILTER
config BPFILTER_UMH
tristate "bpfilter kernel module with user mode helper"
- depends on CC_CAN_LINK_STATIC
+ depends on CC_CAN_LINK
+ depends on m || CC_CAN_LINK_STATIC
default m
help
This builds bpfilter kernel module with embedded user mode helper
- Note: your toolchain must support building static binaries, since
- rootfs isn't mounted at the time when __init functions are called
- and do_execv won't be able to find the elf interpreter.
+ Note: To compile this as built-in, your toolchain must support
+ building static binaries, since rootfs isn't mounted at the time
+ when __init functions are called and do_execv won't be able to find
+ the elf interpreter.
endif
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index f23b53294fba..cdac82b8c53a 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -7,10 +7,12 @@ userprogs := bpfilter_umh
bpfilter_umh-objs := main.o
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
+ifeq ($(CONFIG_BPFILTER_UMH), y)
# builtin bpfilter_umh should be linked with -static
# since rootfs isn't mounted at the time of __init
# function is called and do_execv won't find elf interpreter
userldflags += -static
+endif
$(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
--
2.25.1
