[PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Maxime Chevallier (Netdev Foundation)]

After the blamed commit, running a out-of-tree build for ynltool fails :

  # make -C tools/net/ynl/ynltool O=/tmp/o1
  make: Entering directory 'tools/net/ynl/ynltool'
  make: *** No rule to make target '/tmp/o1/json_writer.o', needed by '/tmp/o1/ynltool'.  Stop.

ynltool's Makefile correctly accounts for $(OUTPUT) to get the list of
object files to generate :

OBJS := $(patsubst %.c,$(OUTPUT)%.o,$(SRCS))

but it never actually set $(OUTPUT) before the blamed commit, meaning
that out-of-tree buils of ynltool were always actually in-tree.

Now, the O= parameter is correctly accounted for, and the %o: %c rule fails.

Let's update the %o: %c rule to also use $(OUTPUT).

Reported-by: Bobby Eshleman <bobbyeshleman@gmail.com>
Closes: https://lore.kernel.org/all/aqCyWQxqKDuQnZYR@devvm29614.prn0.facebook.com/
Fixes: 917f713b4ec4 ("tools: ynl: Allow cross-compiling ynl and associated tools")
Signed-off-by: Maxime Chevallier (Netdev Foundation) <maxime.chevallier@bootlin.com>
---
Targetting net-next, as the blamed commit lives there.

 tools/net/ynl/ynltool/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/net/ynl/ynltool/Makefile b/tools/net/ynl/ynltool/Makefile
index b8c67cdb4fdf..1053e7606c86 100644
--- a/tools/net/ynl/ynltool/Makefile
+++ b/tools/net/ynl/ynltool/Makefile
@@ -31,7 +31,7 @@ $(YNLTOOL): ../libynl.a $(OBJS)
 	$(Q)echo -e "\tLINK $@"
 	$(Q)$(CC) $(CFLAGS) -o $@ $(OBJS) ../libynl.a -lm
 
-%.o: %.c ../libynl.a
+$(OUTPUT)%.o: %.c ../libynl.a
 	$(Q)echo -e "\tCC $@"
 	$(Q)$(COMPILE.c) -MMD -c -o $@ $<
 
-- 
2.55.0

Re: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Jakub Kicinski]

On Wed,  9 Sep 2026 09:11:54 +0200 Maxime Chevallier (Netdev
Foundation) wrote:
> thomas.petazzoni@bootlin.com, linux-kselftest@vger.kernel.org
> Subject: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

Hi Maxime, thanks for the quick fix. Looks like this did not hit
netdev, unfortunately. It reached lore but via a different ML,
and our patchwork only trails netdev itself. Please repost.

Re: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Maxime Chevallier]

Hi,

On 9/10/26 17:59, Jakub Kicinski wrote:
> On Wed,  9 Sep 2026 09:11:54 +0200 Maxime Chevallier (Netdev
> Foundation) wrote:
>> thomas.petazzoni@bootlin.com, linux-kselftest@vger.kernel.org
>> Subject: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool
> 
> Hi Maxime, thanks for the quick fix. Looks like this did not hit
> netdev, unfortunately. It reached lore but via a different ML,
> and our patchwork only trails netdev itself. Please repost.

Dammit, seems like most of the patches I sent yesterday failed in a
similar fashion :(

I'll resend right-away, sorry about that,

Maxime

Re: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Bobby Eshleman]

On Wed, Sep 09, 2026 at 09:11:54AM +0200, Maxime Chevallier (Netdev Foundation) wrote:
> After the blamed commit, running a out-of-tree build for ynltool fails :
> 
>   # make -C tools/net/ynl/ynltool O=/tmp/o1
>   make: Entering directory 'tools/net/ynl/ynltool'
>   make: *** No rule to make target '/tmp/o1/json_writer.o', needed by '/tmp/o1/ynltool'.  Stop.
> 
> ynltool's Makefile correctly accounts for $(OUTPUT) to get the list of
> object files to generate :
> 
> OBJS := $(patsubst %.c,$(OUTPUT)%.o,$(SRCS))
> 
> but it never actually set $(OUTPUT) before the blamed commit, meaning
> that out-of-tree buils of ynltool were always actually in-tree.
> 
> Now, the O= parameter is correctly accounted for, and the %o: %c rule fails.
> 
> Let's update the %o: %c rule to also use $(OUTPUT).
> 
> Reported-by: Bobby Eshleman <bobbyeshleman@gmail.com>
> Closes: https://lore.kernel.org/all/aqCyWQxqKDuQnZYR@devvm29614.prn0.facebook.com/
> Fixes: 917f713b4ec4 ("tools: ynl: Allow cross-compiling ynl and associated tools")
> Signed-off-by: Maxime Chevallier (Netdev Foundation) <maxime.chevallier@bootlin.com>
> ---
> Targetting net-next, as the blamed commit lives there.
> 
>  tools/net/ynl/ynltool/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/net/ynl/ynltool/Makefile b/tools/net/ynl/ynltool/Makefile
> index b8c67cdb4fdf..1053e7606c86 100644
> --- a/tools/net/ynl/ynltool/Makefile
> +++ b/tools/net/ynl/ynltool/Makefile
> @@ -31,7 +31,7 @@ $(YNLTOOL): ../libynl.a $(OBJS)
>  	$(Q)echo -e "\tLINK $@"
>  	$(Q)$(CC) $(CFLAGS) -o $@ $(OBJS) ../libynl.a -lm
>  
> -%.o: %.c ../libynl.a
> +$(OUTPUT)%.o: %.c ../libynl.a
>  	$(Q)echo -e "\tCC $@"
>  	$(Q)$(COMPILE.c) -MMD -c -o $@ $<
>  
> -- 
> 2.55.0
> 

Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>

Re: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Maxime Chevallier]

Hi Bobby,

On 9/10/26 19:10, Bobby Eshleman wrote:
> On Wed, Sep 09, 2026 at 09:11:54AM +0200, Maxime Chevallier (Netdev Foundation) wrote:
>> After the blamed commit, running a out-of-tree build for ynltool fails :
>>
>>   # make -C tools/net/ynl/ynltool O=/tmp/o1
>>   make: Entering directory 'tools/net/ynl/ynltool'
>>   make: *** No rule to make target '/tmp/o1/json_writer.o', needed by '/tmp/o1/ynltool'.  Stop.
>>
>> ynltool's Makefile correctly accounts for $(OUTPUT) to get the list of
>> object files to generate :
>>
>> OBJS := $(patsubst %.c,$(OUTPUT)%.o,$(SRCS))
>>
>> but it never actually set $(OUTPUT) before the blamed commit, meaning
>> that out-of-tree buils of ynltool were always actually in-tree.
>>
>> Now, the O= parameter is correctly accounted for, and the %o: %c rule fails.
>>
>> Let's update the %o: %c rule to also use $(OUTPUT).
>>
>> Reported-by: Bobby Eshleman <bobbyeshleman@gmail.com>
>> Closes: https://lore.kernel.org/all/aqCyWQxqKDuQnZYR@devvm29614.prn0.facebook.com/
>> Fixes: 917f713b4ec4 ("tools: ynl: Allow cross-compiling ynl and associated tools")
>> Signed-off-by: Maxime Chevallier (Netdev Foundation) <maxime.chevallier@bootlin.com>

[...]

> Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>

Thanks :)

Nicolai noted that there's another improvement to be made, as we don't
account for modifications made to .h files. The diff would be :

-include $(wildcard *.d)
+include $(wildcard $(OUTPUT)*.d)

See [1].

May I keep your review tag if I add the above diff in v2 ?

Thanks,

Maxime

[1] : https://lore.kernel.org/all/c44d371714839566a02cd9c944c7e177@tipi-net.de/

Re: [PATCH net-next] tools: ynl: Fix out-of-tree build for ynltool

[Bobby Eshleman]

On Thu, Sep 10, 2026 at 11:12:24PM +0200, Maxime Chevallier wrote:
> Hi Bobby,
> 
> On 9/10/26 19:10, Bobby Eshleman wrote:
> > On Wed, Sep 09, 2026 at 09:11:54AM +0200, Maxime Chevallier (Netdev Foundation) wrote:
> >> After the blamed commit, running a out-of-tree build for ynltool fails :
> >>
> >>   # make -C tools/net/ynl/ynltool O=/tmp/o1
> >>   make: Entering directory 'tools/net/ynl/ynltool'
> >>   make: *** No rule to make target '/tmp/o1/json_writer.o', needed by '/tmp/o1/ynltool'.  Stop.
> >>
> >> ynltool's Makefile correctly accounts for $(OUTPUT) to get the list of
> >> object files to generate :
> >>
> >> OBJS := $(patsubst %.c,$(OUTPUT)%.o,$(SRCS))
> >>
> >> but it never actually set $(OUTPUT) before the blamed commit, meaning
> >> that out-of-tree buils of ynltool were always actually in-tree.
> >>
> >> Now, the O= parameter is correctly accounted for, and the %o: %c rule fails.
> >>
> >> Let's update the %o: %c rule to also use $(OUTPUT).
> >>
> >> Reported-by: Bobby Eshleman <bobbyeshleman@gmail.com>
> >> Closes: https://lore.kernel.org/all/aqCyWQxqKDuQnZYR@devvm29614.prn0.facebook.com/
> >> Fixes: 917f713b4ec4 ("tools: ynl: Allow cross-compiling ynl and associated tools")
> >> Signed-off-by: Maxime Chevallier (Netdev Foundation) <maxime.chevallier@bootlin.com>
> 
> [...]
> 
> > Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
> 
> Thanks :)
> 
> Nicolai noted that there's another improvement to be made, as we don't
> account for modifications made to .h files. The diff would be :
> 
> -include $(wildcard *.d)
> +include $(wildcard $(OUTPUT)*.d)
> 
> See [1].
> 
> May I keep your review tag if I add the above diff in v2 ?
> 
> Thanks,
> 
> Maxime

Yes, np, feel free to carry it forward!

Best,
Bobby