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AJvYcCUS6ksGZnsnj9X4gRtnSBzggiFexkg1Xmx6JHdk4QAfK3/pOO82jtO32JOl6WpxYjTHJksO@lists.linux.dev X-Gm-Message-State: AOJu0Yxcd/lYW/ubLfmT8f5gYnLXplz9JPcVWXxSFunam+cm+xc4Ay5B 5EANznCN/JFS/nqyOlqzoFU3byResNrA1Pm8qX+Cbe9y2da3jbDJmkHr8qcK4l1JABL8PgDsZ0W q/0CqSABrupSsLbNeLg== X-Google-Smtp-Source: AGHT+IEdrDcqbH7vAlZv1Rn1uYyJ5HQB5sQCRxjZt52n+6AQMlVKXOnSQHUlYVs8jycmYRM0JYcUHwiCmoajA+c= X-Received: from wmbjd14.prod.google.com ([2002:a05:600c:68ce:b0:474:979d:a20d]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:45cf:b0:477:7d94:5d0e with SMTP id 5b1f17b1804b1-477c01eb9b2mr15025395e9.27.1763716090113; Fri, 21 Nov 2025 01:08:10 -0800 (PST) Date: Fri, 21 Nov 2025 09:08:09 +0000 In-Reply-To: Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <202511210055.RUsFNku1-lkp@intel.com> Message-ID: Subject: Re: [linux-next:master 9676/10599] ld.lld: error: undefined symbol: rust_build_error From: Alice Ryhl To: Alexandre Courbot Cc: kernel test robot , Miguel Ojeda , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev Content-Type: text/plain; charset="utf-8" On Fri, Nov 21, 2025 at 03:13:16PM +0900, Alexandre Courbot wrote: > On Fri Nov 21, 2025 at 1:41 AM JST, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 88cbd8ac379cf5ce68b7efcfd4d1484a6871ee0b > > commit: 01e345e82ec3a5a7edeb9fa0dcb7fd4b0e5c534e [9676/10599] rust: num: add Bounded integer wrapping type > > config: loongarch-randconfig-6002-20251120 (https://download.01.org/0day-ci/archive/20251121/202511210055.RUsFNku1-lkp@intel.com/config) > > compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff) > > rustc: rustc 1.88.0 (6b00bc388 2025-06-23) > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251121/202511210055.RUsFNku1-lkp@intel.com/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot > > | Closes: https://lore.kernel.org/oe-kbuild-all/202511210055.RUsFNku1-lkp@intel.com/ > > > > All errors (new ones prefixed by >>): > > > >>> ld.lld: error: undefined symbol: rust_build_error > > >>> referenced by build_assert.rs:83 (rust/kernel/build_assert.rs:83) > > >>> rust/doctests_kernel_generated.o:(>::from_expr) in archive vmlinux.a > > >>> referenced by build_assert.rs:83 (rust/kernel/build_assert.rs:83) > > >>> rust/doctests_kernel_generated.o:(>::from_expr) in archive vmlinux.a > > >>> referenced by build_assert.rs:83 (rust/kernel/build_assert.rs:83) > > >>> rust/doctests_kernel_generated.o:(>::from_expr) in archive vmlinux.a > > Mmm, I don't like this. The expressions that are failing are extremely > simple, for instance: > > Bounded::::from_expr(1) > > So if the compiler is unable to assess that this won't fail, this might > be a deal-breaker for `from_expr` and we might need to remove it. :( > > This would also mean a lot more runtime checks when working with > bitfields and registers. Or can we assume that this is a compiler > problem on this particular architecture? Yeah, it sounds like from_expr() isn't going to work. Alice