"checkpatch.pl --mailback" broken?

From: Jakob Unterwurzacher

Date: Fri Oct 30 2026 - 06:23:26 EST


Hi there,

looks like I recently hit [1] an interesting corner-case in checkpatch.pl . When passing "--mailback", it seems to exit early with success, despite having errors in the patches. In my case, it was missing Signed-off-by.

Here's what happened:

$ b4 --version
0.16.0
$ b4 prep --check
Checking patches using:
/home/junterwurzacher/tiger/linux-tiger-v7.4-pre-tiger-suspend/scripts/checkpatch.pl -q --terse --no-summary --mailback --showfile
---
● efd1aef7f361: Input: rk805-pwrkey - enable the wakeup interrupt during system suspend
[...]
---
Success: 4, Warning: 0, Error: 0

Calling checkpatch.pl manually with the same command line:

$ ./scripts/checkpatch.pl -q --terse --no-summary --mailback --showfile 0001-arm64-dts-rockchip-put-the-PMIC-into-sleep-mode-in-s.patch
(no output, exit code 0)

Dropping "--mailback" gives the expected ERROR.

$ ./scripts/checkpatch.pl -q --terse --no-summary --showfile 0001-arm64-dts-rockchip-put-the-PMIC-into-sleep-mode-in-s.patch
arch/arm64/boot/dts/rockchip/rk3588-tiger.dtsi:501: ERROR: Missing Signed-off-by: line(s)

I have not analyzed it further yet.

Thanks,
Jakob


[1] https://lore.kernel.org/all/a220ebd0-a28d-44cc-9a80-62382018348c@xxxxxxxxx/