From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 247003655EA; Fri, 2 Oct 2026 09:49:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790934593; cv=none; b=YV1t2imBNPhZgj4VdSo9XXgENrtKBuihKLVFfoP+l08/CRtor6sF3n98fZ8Vjyu6CkmIQXPqpUo0eqLdAS2IR9rXAkHdwx2EhL0rqJoYT4+QSS9X3yyxfFk40lmAa8rdXQPEAmJG09rs/5lTnDwVHyTOpF+yryW1m9Sk6B0JVSc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790934593; c=relaxed/simple; bh=hTWziqKtepDGWLkXqTacUJOldfkRVj3vc6hsj12mp38=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=LIZvdrsn2UtWSIkArzhTN/f/0jD6gv/CBUoHatfNwubISZMIS1ctutZG0HbJqaHbcp1nP1mfjpcrBuBsidTRq+xJZXPx/65LTTQBhMce89tI7BuoTGJyV7vUR0WouEz325jf/Qa1T39i3eqgHfKy1ZyvEItOs/odMdibMluSrWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aOMAm0+c; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aOMAm0+c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89C201F00898; Fri, 2 Oct 2026 09:49:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790934582; bh=O1NvwTXORD+Bb07RA52Wu5WZWJqKJmdYmCUZOMWRc5g=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=aOMAm0+cj8fILcHV8Uj0RSZsjvcpY1RGYRxgNmibtLJucq4PJOFYlIeiGQVMfrMtH DuOOY8IKcr5yOnM73cxavmFw/nMHIjF2qDFrl5uDmTm4oMLgD066mfJFMfXw9Bc49t csqzp1wUBMrdSv3SghZJ/e5GLtijiu6xy2aZ5PO4v+0coTfSNOC/XZkaenDtUej0CP i/q/JrIeY1TU8Nol9o5vJO8rP4m5pAttrz6dh8syfIsV6x0pir8FExIzAdOKEXHnA9 Cm8d729oJ1G8qj87sC00EzJFfXA+tDEZru+V9USQSA1Xg//ndb/O3J7bRLVs8z/I4V zfigDTcHw5t/g== Date: Fri, 2 Oct 2026 11:49:32 +0200 From: Nathan Chancellor To: "Jason A. Donenfeld" Cc: "Christophe Leroy (CS GROUP)" , Nick Desaulniers , Andy Lutomirski , Thomas Gleixner , Theodore Ts'o , Vincenzo Frascino , Bill Wendling , Justin Stitt , Catalin Marinas , Will Deacon , Mark Rutland , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH v2] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data() Message-ID: <20261002094932.GA3435055@ax162> References: <20260930133813.GA3142230@ax162> <20260930151337.GD3142230@ax162> <20261001102059.GA4176271@ax162> <20261001110310.GA138012@ax162> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261001110310.GA138012@ax162> On Thu, Oct 01, 2026 at 01:03:10PM +0200, Nathan Chancellor wrote: > On Thu, Oct 01, 2026 at 12:48:10PM +0200, Jason A. Donenfeld wrote: > > Does this commit seem okay with you? I used the diff you sent below and > > adjusted the commit message: https://git.zx2c4.com/linux-rng/commit/?id=56ff95ee85715047eb5b5220243778af657778c8 > > Yeah, that seems fine to me, thanks for taking care of it! Can you adjust the LLVM value by one from 4294967295 to 4294967294? ~0U is actually a special value, so we hit an assertion in the SystemZ backend. https://github.com/llvm/llvm-project/blob/3f48e22a1f321d5d3341bd812803694cea588785/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp#L9547 https://github.com/llvm/llvm-project/blob/3f48e22a1f321d5d3341bd812803694cea588785/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp#L1470-L1471 clang: llvm/lib/Target/SystemZ/SystemZISelLowering.cpp:1471: virtual bool llvm::SystemZTargetLowering::findOptimalMemOpLowering(LLVMContext &, std::vector &, unsigned int, const MemOp &, unsigned int, unsigned int, const AttributeList &, EVT *) const: Assertion `Limit != ~0U && "Expected EmitTargetCodeForMemXXX() to handle AlwaysInline cases."' failed. PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and dumped files. Stack dump: 0. Program arguments: ... 1. parser at end of file 2. Code generation 3. Running pass 'Function Pass Manager' on module 'arch/s390/kernel/vdso/vgetrandom.c'. 4. Running pass 'SystemZ DAG->DAG Pattern Instruction Selection' on function '@__kernel_getrandom' ... -- Cheers, Nathan