On Wed, Jul 17, 2024, at 08:41, Johan Hovold wrote: > On Wed, Jul 17, 2024 at 08:01:43AM +0200, Arnd Bergmann wrote: >> On Wed, Jul 17, 2024, at 07:08, Linus Torvalds wrote: >> > On Tue, 16 Jul 2024 at 21:57, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> >> >> Note, it really might be just 'allmodconfig'. We've had things that >> >> depend on config entries in the past, eg the whole >> >> CONFIG_HEADERS_INSTALL etc could affect things. >> >> I had tried a partial allmodconfig build earlier to save time, >> did a full build again now, still nothing: > > FWIW, I noticed this last Friday as well when I did a few builds of > linux-next and every change I made triggered what appeared to be a full > rebuild of the tree. > > This was with a trimmed config [1] and separate build tree (tmpfs). Thanks, that makes it quicker to try out. I'm now using your config to do more testing. I still don't see it with a normal build though. I do see that setting the timestamp of syscall.tbl to a future date does result in always rebuilding everything, but I don't think that is what you are seeing, since that also produces a warning from make: arnd@studio:~/arm-soc/build/bisect$ touch -t 202501010000 arch/x86/entry/syscalls/syscall_64.tbl arnd@studio:~/arm-soc/build/bisect$ make ARCH=x86 CROSS_COMPILE=x86_64-linux- make[2]: Warning: File 'arch/x86/entry/syscalls/syscall_64.tbl' has modification time 14483017 s in the future SYSHDR arch/x86/include/generated/uapi/asm/unistd_64.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_x32.h SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h SYSTBL arch/x86/include/generated/asm/syscalls_64.h make[2]: warning: Clock skew detected. Your build may be incomplete. Arnd