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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-486eb2ed0fbsm29878025f8f.3.2026.09.14.14.44.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2026 14:44:47 -0700 (PDT) Date: Mon, 14 Sep 2026 22:44:32 +0100 From: David Laight To: Markus Elfring Cc: Lorenzo Stoakes , linux-kbuild@vger.kernel.org, x86@kernel.org, Albert Ou , Alexandre Courbot , Alexandre Ghiti , Alexey Gladkov , Alice Ryhl , Andreas Hindborg , Ard Biesheuvel , Arnd Bergmann , Benno Lossin , Bill Wendling , =?UTF-8?B?QmrDtnJu?= Roy Baron , Boqun Feng , Borislav Petkov , Catalin Marinas , Daniel Almeida , Danilo Krummrich , Dave Hansen , Gary Guo , "Gustavo A. R. Silva" , "H. Peter Anvin" , Ilias Apalodimas , Ingo Molnar , Jonathan Corbet , Josh Poimboeuf , Justin Stitt , Kees Cook , Linus Torvalds , Mark Rutland , Masahiro Yamada , Miguel Ojeda , Nathan Chancellor , Nick Desaulniers , Nicolas Schier , Onur =?UTF-8?B?w5Z6a2Fu?= , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Randy Dunlap , Tamir Duberstein , Thomas Gleixner , Trevor Gross , Will Deacon , LKML , kernel-janitors@vger.kernel.org, linux-hardening@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Jens Axboe Subject: Re: [PATCH v2 03/21] kallsyms: output binary data to speed output and kallsyms assembly Message-ID: <20260914224432.7ed40d48@pumpkin> In-Reply-To: References: <20260914-build-speedup-v2-3-39817ec5db23@kernel.org> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Mon, 14 Sep 2026 22:16:12 +0200 Markus Elfring wrote: > =E2=80=A6 > > +++ b/scripts/kallsyms.c =20 > =E2=80=A6 > > @@ -413,26 +438,24 @@ static void write_src(void) > > /* Encode length with ULEB128. */ > > if (table[i]->len <=3D 0x7F) { > > /* Most symbols use a single byte for the length. */ > > - printf("\t.byte 0x%02x", table[i]->len); > > + fputc(table[i]->len, out_bin_file); > > off +=3D table[i]->len + 1; > > } else { > > /* "Big" symbols use two bytes. */ > > - printf("\t.byte 0x%02x, 0x%02x", > > - (table[i]->len & 0x7F) | 0x80, > > - (table[i]->len >> 7) & 0x7F); > > + fputc((table[i]->len & 0x7F) | 0x80, out_bin_file); > > + fputc((table[i]->len >> 7) & 0x7F, out_bin_file); > > off +=3D table[i]->len + 2; > > } > > - for (k =3D 0; k < table[i]->len; k++) > > - printf(", 0x%02x", table[i]->sym[k]); > > + fwrite(table[i]->sym, 1, table[i]->len, out_bin_file); > > =20 > > /* > > * Now that we wrote out the compressed symbol name, restore the > > - * original name and print it in the comment. > > + * original name for the comments below. > > */ > > expand_symbol(table[i]->sym, table[i]->len, buf); > > strcpy((char *)table[i]->sym, buf); > > - printf("\t/* %s */\n", table[i]->sym); > > } > > + write_incbin(out_bin_name, bin_start, bin_pos(out_bin_file)); > > printf(".size kallsyms_names, . - kallsyms_names\n"); > > printf("\n"); > > =20 > =E2=80=A6 >=20 > I suggest to avoid return value ignorance a bit more. > https://cmu-sei.github.io/secure-coding-standards/sei-cert-c-coding-stand= ard/rules/error-handling-err/err33-c/ > https://cwe.mitre.org/data/definitions/252.html And I suggest you do some real coding... The error is sticky and can be checked using ferror(). Code that looks at the return value from fprintf() fwrite() etc is very often broken because the only time they can actual fail is when the buffer is flushed during close. Adding error checks to every call just make the code unreadable. David >=20 > Regards, > Markus