myxoid · GitHub

These are actually Android Common Kernel branches, but I've no reason to suspect things will be different on other trees.

Switching from Clang 17 to 18 results in new, unexpected warnings and, with -Werror, builds fail.

6.1: https://android-review.googlesource.com/c/kernel/common/+/2875956
6.6: https://android-review.googlesource.com/c/kernel/common/+/2875957
mainline (https://android.googlesource.com/kernel/common/+/32f6c6538caedab053cfb60e0e7d0e6d7e8e6659): https://android-review.googlesource.com/c/kernel/common/+/2875955

The kernels are built in a variety of configurations (including for different architectures).

The failures have in common is the use of __attribute__((__used__)) via __used.

A typical failure for x86_64 looks like (note that __ADDRESSABLE uses __used):

In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/arch/x86/kernel/asm-offsets.c:9:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/crypto.h:15:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/completion.h:12:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/swait.h:7:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/spinlock.h:95:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/arch/x86/include/asm/spinlock.h:10:
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/arch/x86/include/asm/paravirt.h:31:9: error: unused variable '__UNIQUE_ID___addressable___SCK__pv_sched_clock39' [-Werror,-Wunused-variable]
   31 |         return static_call(pv_sched_clock)();
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/static_call_types.h:90:27: note: expanded from macro 'static_call'
   90 | #define static_call(name)       __static_call(name)
      |                                 ^~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/static_call_types.h:57:2: note: expanded from macro '__static_call'
   57 |         __STATIC_CALL_ADDRESSABLE(name);                                \
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/static_call_types.h:53:2: note: expanded from macro '__STATIC_CALL_ADDRESSABLE'
   53 |         __ADDRESSABLE(STATIC_CALL_KEY(name))
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/compiler_types.h:84:22: note: expanded from macro '__PASTE'
   84 | #define __PASTE(a,b) ___PASTE(a,b)
      |                      ^~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/107/execroot/__main__/common/include/linux/compiler_types.h:83:23: note: expanded from macro '___PASTE'
   83 | #define ___PASTE(a,b) a##b
      |                       ^~~~
<scratch space>:159:1: note: expanded from here
  159 | __UNIQUE_ID___addressable___SCK__pv_sched_clock39
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Wheres for aarch64:

In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/arch/arm64/kernel/asm-offsets.c:10:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/arm_sdei.h:8:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/acpi/ghes.h:5:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/acpi/apei.h:9:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/acpi.h:13:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/resource_ext.h:11:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/slab.h:16:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/gfp.h:7:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/mmzone.h:8:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/spinlock.h:59:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/irqflags.h:17:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/arch/arm64/include/asm/irqflags.h:10:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/arch/arm64/include/asm/ptrace.h:11:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/arch/arm64/include/asm/cpufeature.h:26:
In file included from /mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/cpumask.h:16:
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/numa.h:34:2: warning: unused variable '_entry_ptr' [-Wunused-variable]
   34 |         pr_info_once("Unknown online node for memory at 0x%llx, assuming node 0\n",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   35 |                         start);
      |                         ~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/printk.h:617:2: note: expanded from macro 'pr_info_once'
  617 |         printk_once(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/printk.h:594:15: note: expanded from macro 'printk_once'
  594 |         DO_ONCE_LITE(printk, fmt, ##__VA_ARGS__)
      |         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/once_lite.h:11:24: note: expanded from macro 'DO_ONCE_LITE'
   11 |         DO_ONCE_LITE_IF(true, func, ##__VA_ARGS__)
      |         ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/printk.h:455:26: note: expanded from macro 'printk'
  455 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
      |                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/printk.h:426:3: note: expanded from macro 'printk_index_wrap'
  426 |                 __printk_index_emit(_fmt, NULL, NULL);                  \
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/mnt/disks/build-disk/src/android/common-android-mainline/out/bazel/output_user_root/5eb738bf612d494239553bcc21fe7c03/sandbox/linux-sandbox/6/execroot/__main__/common/include/linux/printk.h:395:34: note: expanded from macro '__printk_index_emit'
  395 |                         static const struct pi_entry *_entry_ptr        \
      |                                                       ^~~~~~~~~~

Read the original on github.com ↗