Binman creates a single image 4 times

[Quentin Schulz]

Hi all,

I'm signing U-Boot FIT images with binman and that takes some time. If I 
build twice in a row without any change, the build process takes about 
15 seconds, most of it spent in pselect6() according to strace. I have 
yet to discover if it's related to the engine or mkimage or even OpenSSL 
itself. Anyway, nobody likes waiting and it differed from my pre-binman 
U-Boot enough that I "dug" a bit.

Even when not signing, with 
https://elixir.bootlin.com/u-boot/v2025.10/source/tools/binman/bintool.py#L294 
used to report all calls to bintools made by Binman while building the 
image, the expected bintool calls are all unexpectedly (to me) made 4 times:

bintool: mkimage -d 
./mkimage-in-simple-bin.mkimage-u-boot-tpl:./mkimage-in-simple-bin.mkimage-section 
-n px30 -T rksd ./idbloader.img
bintool: mkimage -E -B 200 -t -F ./simple-bin.fit.fit
bintool: mkimage -d 
./mkimage-in-simple-bin.mkimage-u-boot-tpl:./mkimage-in-simple-bin.mkimage-section 
-n px30 -T rksd ./idbloader.img
bintool: mkimage -E -B 200 -t -F ./simple-bin.fit.fit
bintool: mkimage -E -B 200 -t -F ./simple-bin.fit.fit
bintool: mkimage -d 
./mkimage-in-simple-bin.mkimage-u-boot-tpl:./mkimage-in-simple-bin.mkimage-section 
-n px30 -T rksd ./idbloader.img
bintool: mkimage -d 
./mkimage-in-simple-bin.mkimage-u-boot-tpl:./mkimage-in-simple-bin.mkimage-section 
-n px30 -T rksd ./idbloader.img
bintool: mkimage -E -B 200 -t -F ./simple-bin.fit.fit

(in that order).

Printing the stack, it seems like:
- 2 calls are made from 
https://elixir.bootlin.com/u-boot/v2025.10/source/tools/binman/control.py#L789
- 1 call from 
https://elixir.bootlin.com/u-boot/v2025.10/source/tools/binman/control.py#L802
- 1 call from 
https://elixir.bootlin.com/u-boot/v2025.10/source/tools/binman/control.py#L813

Is that intended/expected?

Can be easily reproduced by building ringneck-px30_defconfig for example.

Cheers,
Quentin