kbuild: make scripts/adjust_autoksyms.sh robust against timestamp races
authorNicolas Pitre <nicolas.pitre@linaro.org>
Thu, 15 Mar 2018 20:56:20 +0000 (16:56 -0400)
committerMasahiro Yamada <yamada.masahiro@socionext.com>
Wed, 21 Mar 2018 09:18:10 +0000 (18:18 +0900)
commit825d487583089f9a33d31650c9c41f6474aab7fc
tree5aeb3b755703fca443fdfe3bb40da5ba355515ca
parent0c8efd610b58cb23cefdfa12015799079aef94ae
kbuild: make scripts/adjust_autoksyms.sh robust against timestamp races

Some filesystems have timestamps with coarse precision that may allow
for a recently built object file to have the same timestamp as the
updated time on one of its dependency files. When that happens, the
object file doesn't get rebuilt as it should.

This is especially the case on filesystems that don't have sub-second
time precision, such as ext3 or Ext4 with 128B inodes.

Let's prevent that by making sure updated dependency files have a newer
timestamp than the first file we created (i.e. autoksyms.h.tmpnew).

Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
scripts/adjust_autoksyms.sh