Bug 11641 - linux kernel .config timestamp always out of date fixed with KCONFIG_NOSILENTUPDATE
Summary: linux kernel .config timestamp always out of date fixed with KCONFIG_NOSILENT...
Status: RESOLVED FIXED
Alias: None
Product: buildroot
Classification: Unclassified
Component: Other (show other bugs)
Version: 2018.11.1
Hardware: All Linux
: P5 normal
Target Milestone: ---
Assignee: unassigned
URL:
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Reported: 2019-01-24 16:33 UTC by Doug Crawford
Modified: 2019-08-15 13:19 UTC (History)
1 user (show)

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Description Doug Crawford 2019-01-24 16:33:26 UTC 
Just noticed this when migrating from kernel 4.9 to 4.19.  I noticed that now in the linux kernel build dir the .config timestamp is always later than the .stamp_kconfig_fixup_done.  So every incremental buildroot make causes the kernel build to always run starting at the kconfig fixup phase.

I traced the problem to somewhere in the kernel syncconfig step in the kernel "build" phase.  I think it is related to this new kernel 4.19 commit.

16952b77d8 kconfig: make syncconfig update .config regardless of sym_change_count

If I define KCONFIG_NOSILENTUPDATE in my environment the problem goes away and the timestamps are correct.  Should buildroot set this env variable?  I am not sure what the other side affects would be.
Comment 1 Thomas Petazzoni 2019-08-15 13:19:29 UTC 
Thanks for your bug report! This was fixed by commit https://git.buildroot.org/buildroot/commit/?id=05fea6e4a60a38a797d9bacbf318a2cd7dbd435f.