On Fri,  5 Dec 2025 12:52:35 -0500 "Yury Norov (NVIDIA)" [off-list ref] wrote:

Tracing is a half of the kernel.h in terms of LOCs, although it's
a self-consistent part. It is intended for quick debugging purposes
and isn't used by the normal tracing utilities.

Move it to a separate header. If someone needs to just throw a
trace_printk() in their driver, they will not have to pull all
the heavy tracing machinery.

This is a pure move, except for removing a few 'extern's.

This one blows up my x86_64 allmodconfig, gcc-15.2.0:

In file included from ./include/linux/string.h:386,
                 from ./include/linux/trace_printk.h:9,
                 from ./include/linux/kernel.h:34,
                 from arch/x86/purgatory/purgatory.c:12:
./include/linux/fortify-string.h:626:63: error: expected identifier or '(' before '{' token
  626 |                              p_size_field, q_size_field, op) ({         \
      |                                                               ^
./include/linux/fortify-string.h:694:27: note: in expansion of macro '__fortify_memcpy_chk'
  694 | #define memmove(p, q, s)  __fortify_memcpy_chk(p, q, s,                 \
      |                           ^~~~~~~~~~~~~~~~~~~~
arch/x86/purgatory/../boot/string.h:11:7: note: in expansion of macro 'memmove'
   11 | void *memmove(void *dst, const void *src, size_t len);
      |       ^~~~~~~
./include/linux/fortify-string.h:258:9: error: expected identifier or '(' before '__builtin_choose_expr'
  258 |         __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)),      \
      |         ^~~~~~~~~~~~~~~~~~~~~
arch/x86/purgatory/../boot/string.h:23:15: note: in expansion of macro 'strlen'
   23 | extern size_t strlen(const char *s);
      |               ^~~~~~
make[4]: *** [scripts/Makefile.build:287: arch/x86/purgatory/purgatory.o] Error 1
make[3]: *** [scripts/Makefile.build:556: arch/x86/purgatory] Error 2
make[2]: *** [scripts/Makefile.build:556: arch/x86] Error 2
make[1]: *** [/usr/src/25/Makefile:2054: .] Error 2
make: *** [Makefile:248: __sub-make] Error 2