No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Nathan Chancellor 86a8bec7cc kbuild: Disable -Wdefault-const-init-unsafe
commit d0afcfeb9e3810ec89d1ffde1a0e36621bb75dca upstream.

A new on by default warning in clang [1] aims to flags instances where
const variables without static or thread local storage or const members
in aggregate types are not initialized because it can lead to an
indeterminate value. This is quite noisy for the kernel due to
instances originating from header files such as:

  drivers/gpu/drm/i915/gt/intel_ring.h:62:2: error: default initialization of an object of type 'typeof (ring->size)' (aka 'const unsigned int') leaves the object uninitialized [-Werror,-Wdefault-const-init-var-unsafe]
     62 |         typecheck(typeof(ring->size), next);
        |         ^
  include/linux/typecheck.h:10:9: note: expanded from macro 'typecheck'
     10 | ({      type __dummy; \
        |              ^

  include/net/ip.h:478:14: error: default initialization of an object of type 'typeof (rt->dst.expires)' (aka 'const unsigned long') leaves the object uninitialized [-Werror,-Wdefault-const-init-var-unsafe]
    478 |                 if (mtu && time_before(jiffies, rt->dst.expires))
        |                            ^
  include/linux/jiffies.h:138:26: note: expanded from macro 'time_before'
    138 | #define time_before(a,b)        time_after(b,a)
        |                                 ^
  include/linux/jiffies.h:128:3: note: expanded from macro 'time_after'
    128 |         (typecheck(unsigned long, a) && \
        |          ^
  include/linux/typecheck.h:11:12: note: expanded from macro 'typecheck'
     11 |         typeof(x) __dummy2; \
        |                   ^

  include/linux/list.h:409:27: warning: default initialization of an object of type 'union (unnamed union at include/linux/list.h:409:27)' with const member leaves the object uninitialized [-Wdefault-const-init-field-unsafe]
    409 |         struct list_head *next = smp_load_acquire(&head->next);
        |                                  ^
  include/asm-generic/barrier.h:176:29: note: expanded from macro 'smp_load_acquire'
    176 | #define smp_load_acquire(p) __smp_load_acquire(p)
        |                             ^
  arch/arm64/include/asm/barrier.h:164:59: note: expanded from macro '__smp_load_acquire'
    164 |         union { __unqual_scalar_typeof(*p) __val; char __c[1]; } __u;   \
        |                                                                  ^
  include/linux/list.h:409:27: note: member '__val' declared 'const' here

  crypto/scatterwalk.c:66:22: error: default initialization of an object of type 'struct scatter_walk' with const member leaves the object uninitialized [-Werror,-Wdefault-const-init-field-unsafe]
     66 |         struct scatter_walk walk;
        |                             ^
  include/crypto/algapi.h:112:15: note: member 'addr' declared 'const' here
    112 |                 void *const addr;
        |                             ^

  fs/hugetlbfs/inode.c:733:24: error: default initialization of an object of type 'struct vm_area_struct' with const member leaves the object uninitialized [-Werror,-Wdefault-const-init-field-unsafe]
    733 |         struct vm_area_struct pseudo_vma;
        |                               ^
  include/linux/mm_types.h:803:20: note: member 'vm_flags' declared 'const' here
    803 |                 const vm_flags_t vm_flags;
        |                                  ^

Silencing the instances from typecheck.h is difficult because '= {}' is
not available in older but supported compilers and '= {0}' would cause
warnings about a literal 0 being treated as NULL. While it might be
possible to come up with a local hack to silence the warning for
clang-21+, it may not be worth it since -Wuninitialized will still
trigger if an uninitialized const variable is actually used.

In all audited cases of the "field" variant of the warning, the members
are either not used in the particular call path, modified through other
means such as memset() / memcpy() because the containing object is not
const, or are within a union with other non-const members.

Since this warning does not appear to have a high signal to noise ratio,
just disable it.

Cc: stable@vger.kernel.org
Link: 576161cb60 [1]
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/CA+G9fYuNjKcxFKS_MKPRuga32XbndkLGcY-PVuoSwzv6VWbY=w@mail.gmail.com/
Reported-by: Marcus Seyfarth <m.seyfarth@gmail.com>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2088
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[nathan: Apply change to Makefile instead of scripts/Makefile.extrawarn
         due to lack of e88ca24319e4 in older stable branches]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-04 14:32:36 +02:00
arch MIPS: pm-cps: Use per-CPU variables as per-CPU, not per-core 2025-06-04 14:32:33 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-04-10 14:29:37 +02:00
certs
crypto crypto: algif_hash - fix double free in hash_accept 2025-06-04 14:32:35 +02:00
Documentation x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2 2025-06-04 14:32:32 +02:00
drivers spi: spi-fsl-dspi: restrict register range for regmap access 2025-06-04 14:32:36 +02:00
fs __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock 2025-06-04 14:32:35 +02:00
include ALSA: pcm: Fix race of buffer access at PCM OSS layer 2025-06-04 14:32:35 +02:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:39:28 +02:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y 2025-06-04 14:32:34 +02:00
lib dql: Fix dql->limit value when reset. 2025-06-04 14:32:30 +02:00
LICENSES
mm mm/page_alloc.c: avoid infinite retries caused by cpuset race 2025-06-04 14:32:36 +02:00
net llc: fix data loss when reading from a socket in llc_ui_recvmsg() 2025-06-04 14:32:35 +02:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts kbuild: fix argument parsing in scripts/config 2025-06-04 14:32:31 +02:00
security smack: recognize ipv4 CIPSO w/o categories 2025-06-04 14:32:33 +02:00
sound ALSA: pcm: Fix race of buffer access at PCM OSS layer 2025-06-04 14:32:35 +02:00
tools bpftool: Fix readlink usage in get_fd_type 2025-06-04 14:32:34 +02:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile kbuild: Disable -Wdefault-const-init-unsafe 2025-06-04 14:32:36 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.