linux-kernel - Re: [PATCH] selftests/filesystems:fix build error in overlayfs

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 linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <ZaVAjQmio26WloSk@google.com>
Date: Mon, 15 Jan 2024 15:26:21 +0100
From: "Günther Noack" <gnoack@...gle.com>
To: Hu Yadi <hu.yadi@....com>
Cc: jmorris@...ei.org, serge@...lyn.com, shuah@...nel.org, 
	mathieu.desnoyers@...icios.com, mic@...ikod.net, amir73il@...il.com, 
	brauner@...nel.org, avagin@...gle.com, linux-api@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-security-module@...r.kernel.org, 
	linux-kselftest@...r.kernel.org, 514118380@...com
Subject: Re: [PATCH] selftests/filesystems:fix build error in overlayfs

Hello!

On Fri, Jan 12, 2024 at 03:40:59PM +0800, Hu Yadi wrote:
> One build issue comes up due to both mount.h included dev_in_maps.c
> 
> In file included from dev_in_maps.c:10:
> /usr/include/sys/mount.h:35:3: error: expected identifier before numeric constant
>    35 |   MS_RDONLY = 1,  /* Mount read-only.  */
>       |   ^~~~~~~~~
> In file included from dev_in_maps.c:13:
> 
> Remove one of them to solve conflict, another error comes up:
> 
> dev_in_maps.c:170:6: error: implicit declaration of function ‘mount’ [-Werror=implicit-function-declaration]
>   170 |  if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) == -1) {
>       |      ^~~~~
> cc1: all warnings being treated as errors
> 
> and then , add sys_mount definition to solve it
> After both above, dev_in_maps.c can be built correctly on my mache(gcc 102,glibc-2.32,kernel-5.10)

This is apparently the same error as in
https://lore.kernel.org/all/11cdac1e-e96c-405f-63e8-35b0e2926337@arm.com/

I'm getting the impression that we are fixing the issue at the wrong layer here?
After all, the mount() syscall is supposed to be used with <sys/mount.h>
according to the mount(2) man page?  It feels a bit like cheating to resort to
sys_mount() instead...?

Do you have any deeper thoughts on what could be the underlying issue here?
With my newer GCC toolchains, I have been unable to reproduce this.

Thanks,
—Günther