lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 17 Oct 2021 21:09:05 +0200 From: Arnd Bergmann <arnd@...db.de> To: Randy Dunlap <rdunlap@...radead.org> Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Arnd Bergmann <arnd@...db.de>, linux-arch <linux-arch@...r.kernel.org>, Geert Uytterhoeven <geert@...ux-m68k.org>, linux-m68k <linux-m68k@...ts.linux-m68k.org> Subject: Re: [PATCH] asm-generic: bug.h: add unreachable() in BUG() for CONFIG_BUG not set On Sun, Oct 17, 2021 at 7:49 PM Randy Dunlap <rdunlap@...radead.org> wrote: > > When CONFIG_BUG is not set/enabled, there is a warning > on ARCH=m68k, gcc version 11.1.0-nolibc from Arnd's crosstools: > > ../fs/afs/dir.c: In function 'afs_dir_set_page_dirty': > ../fs/afs/dir.c:51:1: error: no return statement in function returning non-void [-Werror=return-type] > > Adding "unreachable()" in the BUG() macro silences the warning. No, I don't think this is the right solution: > -#define BUG() do {} while (1) > +#define BUG() do {unreachable();} while (1) Marking this code unreachable() means the compiler is free to assume any code path leading here will never be entered, which leads to additional undefined behavior and other warnings rather than just hanging reproducibly. The endless loop here should normally be sufficient to tell the compiler that the function never returns, so it sounds like a problem in gcc for m68k. Did you see any other issues like this one on m68k, or the same one on another architecture? Arnd
Powered by blists - more mailing lists