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 <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
---
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
On Wed, Jul 01, 2020 at 06:26:44PM +0900, Masahiro Yamada wrote:
> 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 <[email protected]>
> Signed-off-by: Masahiro Yamada <[email protected]>
Tested-by: Michal Kubecek <[email protected]>
Thank you,
Michal
> ---
>
> 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
>
On Wed, Jul 01, 2020 at 06:26:44PM +0900, Masahiro Yamada wrote:
> 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 <[email protected]>
> Signed-off-by: Masahiro Yamada <[email protected]>
lgtm
Do you mind I'll take it into bpf-next tree?
Eric is working on a bunch of patches in this area. I'll take his set
into bpf-next as well and then can apply this patch.
Just to make sure there are no conflicts.
On Thu, Jul 2, 2020 at 2:46 AM Alexei Starovoitov
<[email protected]> wrote:
>
> On Wed, Jul 01, 2020 at 06:26:44PM +0900, Masahiro Yamada wrote:
> > 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 <[email protected]>
> > Signed-off-by: Masahiro Yamada <[email protected]>
>
> lgtm
> Do you mind I'll take it into bpf-next tree?
> Eric is working on a bunch of patches in this area. I'll take his set
> into bpf-next as well and then can apply this patch.
> Just to make sure there are no conflicts.
Please go ahead.
Thank you.
--
Best Regards
Masahiro Yamada
On Wed, Jul 1, 2020 at 10:50 AM Masahiro Yamada <[email protected]> wrote:
>
> On Thu, Jul 2, 2020 at 2:46 AM Alexei Starovoitov
> <[email protected]> wrote:
> >
> > On Wed, Jul 01, 2020 at 06:26:44PM +0900, Masahiro Yamada wrote:
> > > 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 <[email protected]>
> > > Signed-off-by: Masahiro Yamada <[email protected]>
> >
> > lgtm
> > Do you mind I'll take it into bpf-next tree?
> > Eric is working on a bunch of patches in this area. I'll take his set
> > into bpf-next as well and then can apply this patch.
> > Just to make sure there are no conflicts.
>
> Please go ahead.
I've merged Eric's set and applied yours on top.
Thanks