Lots of "error: multiple storage classes" warnings on the Linux kernel

Lots of "error: multiple storage classes" warnings on the Linux kernel

[Bernd Petrovitsch]

Hi all!

While investigating something completely different, I noticed lots of 
"error: multiple storage classes" warnings, e.g.
----  snip  ----
  CHECK   security/keys/keyring.c
include/linux/sched.h:831:12: error: multiple storage classes: extern weak
security/keys/keyring.c:75:1: error: multiple storage classes: extern weak
security/keys/keyring.c:471:1: error: multiple storage classes: extern weak
security/keys/keyring.c:899:1: error: multiple storage classes: extern weak
security/keys/keyring.c:974:1: error: multiple storage classes: extern weak
security/keys/keyring.c:1033:1: error: multiple storage classes: extern weak
----  snip  ---- 
[ The ": extern weak" is from me to see which are actually set. ]

Is this warning correct that way (and the source should be fixed) or is
the warning in that wrong?

	Bernd 
-- 
mobile: +43 664 4416156              http://www.sysprog.at/
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Re: Lots of "error: multiple storage classes" warnings on the Linux kernel

[Sam Ravnborg]

On Thu, Aug 19, 2010 at 02:53:12PM +0200, Bernd Petrovitsch wrote:
> Hi all!
> 
> While investigating something completely different, I noticed lots of 
> "error: multiple storage classes" warnings, e.g.
> ----  snip  ----
>   CHECK   security/keys/keyring.c
> include/linux/sched.h:831:12: error: multiple storage classes: extern weak
> security/keys/keyring.c:75:1: error: multiple storage classes: extern weak
> security/keys/keyring.c:471:1: error: multiple storage classes: extern weak
> security/keys/keyring.c:899:1: error: multiple storage classes: extern weak
> security/keys/keyring.c:974:1: error: multiple storage classes: extern weak
> security/keys/keyring.c:1033:1: error: multiple storage classes: extern weak
> ----  snip  ---- 
> [ The ": extern weak" is from me to see which are actually set. ]
> 
> Is this warning correct that way (and the source should be fixed) or is
> the warning in that wrong?

Can you cook up a small code snippet that
exhibit this without all the kernel macros etc?
This would make it easier for the sparse folks to understand.

	Sam

Re: Lots of "error: multiple storage classes" warnings on the Linux kernel

[Bernd Petrovitsch]

On Don, 2010-08-19 at 21:26 +0200, Sam Ravnborg wrote:
> On Thu, Aug 19, 2010 at 02:53:12PM +0200, Bernd Petrovitsch wrote:
[...]
> > While investigating something completely different, I noticed lots of 
> > "error: multiple storage classes" warnings, e.g.
> > ----  snip  ----
> >   CHECK   security/keys/keyring.c
> > include/linux/sched.h:831:12: error: multiple storage classes: extern weak
> > security/keys/keyring.c:75:1: error: multiple storage classes: extern weak
> > security/keys/keyring.c:471:1: error: multiple storage classes: extern weak
> > security/keys/keyring.c:899:1: error: multiple storage classes: extern weak
> > security/keys/keyring.c:974:1: error: multiple storage classes: extern weak
> > security/keys/keyring.c:1033:1: error: multiple storage classes: extern weak
> > ----  snip  ---- 
> > [ The ": extern weak" is from me to see which are actually set. ]
> > 
> > Is this warning correct that way (and the source should be fixed) or is
> > the warning in that wrong?
> 
> Can you cook up a small code snippet that
> exhibit this without all the kernel macros etc?

Of course.

> This would make it easier for the sparse folks to understand.

----  snip  ----
{341}echo 'extern int __attribute__((weak)) foobar(void);' | sparse -f -
-:1:12: error: multiple storage classes: extern weak
----  snip  ----
is a minimal example shows that.

	Bernd
-- 
Bernd Petrovitsch                  Email : bernd@petrovitsch.priv.at
                     LUGA : http://www.luga.at