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: <27f1275a-aaff-4cc2-896c-b2c34f08ab73@redhat.com>
Date: Fri, 27 Jun 2025 16:36:14 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: kernel test robot <lkp@...el.com>, netdev@...r.kernel.org,
 Guo Ren <guoren@...nel.org>, linux-csky@...r.kernel.org
Cc: oe-kbuild-all@...ts.linux.dev,
 Willem de Bruijn <willemdebruijn.kernel@...il.com>,
 Jason Wang <jasowang@...hat.com>, Andrew Lunn <andrew+netdev@...n.ch>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 "Michael S. Tsirkin" <mst@...hat.com>, Xuan Zhuo
 <xuanzhuo@...ux.alibaba.com>, Eugenio Pérez
 <eperezma@...hat.com>, Yuri Benditovich <yuri.benditovich@...nix.com>,
 Akihiko Odaki <akihiko.odaki@...nix.com>, Jonathan Corbet <corbet@....net>,
 kvm@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v6 net-next 4/9] vhost-net: allow configuring extended
 features

On 6/27/25 3:11 PM, Paolo Abeni wrote:
> +csky maintainer
> On 6/27/25 8:41 AM, kernel test robot wrote:
>> Hi Paolo,
>>
>> kernel test robot noticed the following build warnings:
>>
>> [auto build test WARNING on net-next/main]
>>
>> url:    https://github.com/intel-lab-lkp/linux/commits/Paolo-Abeni/scripts-kernel_doc-py-properly-handle-VIRTIO_DECLARE_FEATURES/20250624-221751
>> base:   net-next/main
>> patch link:    https://lore.kernel.org/r/23e46bff5333015d92bf0876033750d9fbf555a0.1750753211.git.pabeni%40redhat.com
>> patch subject: [PATCH v6 net-next 4/9] vhost-net: allow configuring extended features
>> config: csky-randconfig-001-20250627 (https://download.01.org/0day-ci/archive/20250627/202506271443.G9cAx8PS-lkp@intel.com/config)
>> compiler: csky-linux-gcc (GCC) 15.1.0
>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250627/202506271443.G9cAx8PS-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 <lkp@...el.com>
>> | Closes: https://lore.kernel.org/oe-kbuild-all/202506271443.G9cAx8PS-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
>>
>>    In file included from include/linux/uaccess.h:12,
>>                     from include/linux/sched/task.h:13,
>>                     from include/linux/sched/signal.h:9,
>>                     from include/linux/rcuwait.h:6,
>>                     from include/linux/percpu-rwsem.h:7,
>>                     from include/linux/fs.h:34,
>>                     from include/linux/compat.h:17,
>>                     from drivers/vhost/net.c:8:
>>    arch/csky/include/asm/uaccess.h: In function '__get_user_fn.constprop':
>>>> arch/csky/include/asm/uaccess.h:147:9: warning: 'retval' is used uninitialized [-Wuninitialized]
>>      147 |         __asm__ __volatile__(                           \
>>          |         ^~~~~~~
>>    arch/csky/include/asm/uaccess.h:187:17: note: in expansion of macro '__get_user_asm_64'
>>      187 |                 __get_user_asm_64(x, ptr, retval);
>>          |                 ^~~~~~~~~~~~~~~~~
>>    arch/csky/include/asm/uaccess.h:170:13: note: 'retval' was declared here
>>      170 |         int retval;
>>          |             ^~~~~~
>>
>>
>> vim +/retval +147 arch/csky/include/asm/uaccess.h
>>
>> da551281947cb2c Guo Ren 2018-09-05  141  
>> e58a41c2226847f Guo Ren 2021-04-21  142  #define __get_user_asm_64(x, ptr, err)			\
>> da551281947cb2c Guo Ren 2018-09-05  143  do {							\
>> da551281947cb2c Guo Ren 2018-09-05  144  	int tmp;					\
>> e58a41c2226847f Guo Ren 2021-04-21  145  	int errcode;					\
>> e58a41c2226847f Guo Ren 2021-04-21  146  							\
>> e58a41c2226847f Guo Ren 2021-04-21 @147  	__asm__ __volatile__(				\
>> e58a41c2226847f Guo Ren 2021-04-21  148  	"1:   ldw     %3, (%2, 0)     \n"		\
>> da551281947cb2c Guo Ren 2018-09-05  149  	"     stw     %3, (%1, 0)     \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  150  	"2:   ldw     %3, (%2, 4)     \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  151  	"     stw     %3, (%1, 4)     \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  152  	"     br      4f              \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  153  	"3:   mov     %0, %4          \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  154  	"     br      4f              \n"		\
>> da551281947cb2c Guo Ren 2018-09-05  155  	".section __ex_table, \"a\"   \n"		\
>> da551281947cb2c Guo Ren 2018-09-05  156  	".align   2                   \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  157  	".long    1b, 3b              \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  158  	".long    2b, 3b              \n"		\
>> da551281947cb2c Guo Ren 2018-09-05  159  	".previous                    \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  160  	"4:                           \n"		\
>> e58a41c2226847f Guo Ren 2021-04-21  161  	: "=r"(err), "=r"(x), "=r"(ptr),		\
>> e58a41c2226847f Guo Ren 2021-04-21  162  	  "=r"(tmp), "=r"(errcode)			\
>> e58a41c2226847f Guo Ren 2021-04-21  163  	: "0"(err), "1"(x), "2"(ptr), "3"(0),		\
>> e58a41c2226847f Guo Ren 2021-04-21  164  	  "4"(-EFAULT)					\
>> da551281947cb2c Guo Ren 2018-09-05  165  	: "memory");					\
>> da551281947cb2c Guo Ren 2018-09-05  166  } while (0)
>> da551281947cb2c Guo Ren 2018-09-05  167  
> 
> The intel test report reported the above compile warning on this series:
> 
> https://lore.kernel.org/netdev/20250627084609-mutt-send-email-mst@kernel.org/T/#md788de2b3a4e9da23ac93b5f1c773a6070b5b4fb
> 
> specifically, in patch 4:
> 
> +                       if (get_user(features, featurep + 1 + i))
> +                               return -EFAULT;
> 
> AFAICS such statement is legit, and the bot points to some problem in
> the arch specific get_user() implementation. Could you please have a look?

Out of sheer ignorance on my side, I fail to see how the csky get_user()
could work correctly without something alike the following (which indeed
fixes the issue here).

/P
---
diff --git a/arch/csky/include/asm/uaccess.h
b/arch/csky/include/asm/uaccess.h
index 2e927c21d8a1..ae0864ad59a3 100644
--- a/arch/csky/include/asm/uaccess.h
+++ b/arch/csky/include/asm/uaccess.h
@@ -167,7 +167,7 @@ do {							\

 static inline int __get_user_fn(size_t size, const void __user *ptr,
void *x)
 {
-	int retval;
+	int retval = 0;
 	u32 tmp;

 	switch (size) {


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ