net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Gabriel C]

Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )

...

net/ipv4/fib_trie.c: In function 'trie_rebalance':
net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'fib_insert_node':
net/ipv4/fib_trie.c:1034: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1034: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1034: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'fn_trie_lookup':
net/ipv4/fib_trie.c:1498: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1502: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1502: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1503: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'trie_leaf_remove':
net/ipv4/fib_trie.c:1539: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1539: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1539: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1554: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'nextleaf':
net/ipv4/fib_trie.c:1706: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c:1743: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'fib_trie_get_next':
net/ipv4/fib_trie.c:2046: error: lvalue required as unary '&' operand
net/ipv4/fib_trie.c: In function 'fib_trie_seq_show':
net/ipv4/fib_trie.c:2320: error: lvalue required as unary '&' operand
make[2]: *** [net/ipv4/fib_trie.o] Error 1
make[1]: *** [net/ipv4] Error 2
make: *** [net] Error 2
make: *** Waiting for unfinished jobs....

...

Re: net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Adrian Bunk]

On Wed, Aug 22, 2007 at 05:30:13PM +0200, Gabriel C wrote:
> Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )
> 
> ...
> 
> net/ipv4/fib_trie.c: In function 'trie_rebalance':
> net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
> net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
> net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
> net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
>...

Side effect of the git-net removal, temporarily removing 
immunize-rcu_dereference-against-crazy-compiler-writers.patch should 
work around it.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Re: net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Gabriel C]

Adrian Bunk wrote:
> On Wed, Aug 22, 2007 at 05:30:13PM +0200, Gabriel C wrote:
>> Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )
>>
>> ...
>>
>> net/ipv4/fib_trie.c: In function 'trie_rebalance':
>> net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
>> net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
>> net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
>> net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
>> ...
> 
> Side effect of the git-net removal, temporarily removing 
> immunize-rcu_dereference-against-crazy-compiler-writers.patch should 
> work around it.

Yes it does , thx Adrian

> 
> cu
> Adrian
> 

Gabriel

Re: 2.6.23-rc3-mm1

[Gabriel C]

Andrew Morton wrote:
> On Wed, 22 Aug 2007 15:33:27 +0200 Gabriel C <nix.or.die@googlemail.com> wrote:
> 
>> ...
>>
>>  CC      arch/i386/boot/cpu.o
>>   CC      arch/i386/boot/cpucheck.o
>> WARNING: "div64_64" [net/netfilter/xt_connbytes.ko] has no CRC!
>>   CC      arch/i386/boot/edd.o
>>   AS      arch/i386/boot/header.o
>>   CC      arch/i386/boot/main.o
> 
> Yeah, I get that too.  I was hoping that someone who had a vague clue
> about what's causing it might fix it also.

Hmm.. I don't know ( added netdev to Cc ) I got one more :

...

WARNING: "div64_64" [net/ipv4/tcp_cubic.ko] has no CRC!

...

Btw when modprobing these the kernel gets tainted

...

[ 5498.536055] nf_conntrack version 0.5.0 (10240 buckets, 40960 max)
[ 5498.554844] xt_connbytes: no version for "div64_64" found: kernel tainted.

...


> 
>> ...
>>
>> config : http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/config
>> build-log: http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/build-log
>>

Re: net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Paul E. McKenney]

On Wed, Aug 22, 2007 at 05:41:11PM +0200, Adrian Bunk wrote:
> On Wed, Aug 22, 2007 at 05:30:13PM +0200, Gabriel C wrote:
> > Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )
> > 
> > ...
> > 
> > net/ipv4/fib_trie.c: In function 'trie_rebalance':
> > net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
> > net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
> > net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
> > net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
> >...
> 
> Side effect of the git-net removal, temporarily removing 
> immunize-rcu_dereference-against-crazy-compiler-writers.patch should 
> work around it.

Alternatively, the following one-line patch to net/ipv4/fib_trie.c could
be used.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---

 fib_trie.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -urpNa -X dontdiff linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c
--- linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c	2007-08-22 09:20:33.000000000 -0700
+++ linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c	2007-08-22 09:47:33.000000000 -0700
@@ -94,7 +94,7 @@ typedef unsigned int t_key;
 #define T_LEAF  1
 #define NODE_TYPE_MASK	0x1UL
 #define NODE_PARENT(node) \
-	((struct tnode *)rcu_dereference(((node)->parent & ~NODE_TYPE_MASK)))
+	((struct tnode *)(rcu_dereference((node)->parent) & ~NODE_TYPE_MASK))
 
 #define NODE_TYPE(node) ((node)->parent & NODE_TYPE_MASK)
 

drivers/net/ppp_generic - __modpost error ( Re: 2.6.23-rc3-mm1 )

[Gabriel C]

Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-9 )
( patch from http://lkml.org/lkml/2007/8/22/273 is needed too or CONFIG_SCSI_ADVANSYS need be N)


...

ERROR: "slhc_init" [drivers/net/ppp_generic.ko] undefined!
ERROR: "slhc_remember" [drivers/net/ppp_generic.ko] undefined!
ERROR: "slhc_uncompress" [drivers/net/ppp_generic.ko] undefined!
ERROR: "slhc_free" [drivers/net/ppp_generic.ko] undefined!
ERROR: "slhc_compress" [drivers/net/ppp_generic.ko] undefined!
ERROR: "slhc_toss" [drivers/net/ppp_generic.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2

...


Regards,

Gabriel

Re: net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Jarek Poplawski]

On 22-08-2007 19:03, Paul E. McKenney wrote:
> On Wed, Aug 22, 2007 at 05:41:11PM +0200, Adrian Bunk wrote:
>> On Wed, Aug 22, 2007 at 05:30:13PM +0200, Gabriel C wrote:
>>> Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )
>>>
>>> ...
>>>
>>> net/ipv4/fib_trie.c: In function 'trie_rebalance':
>>> net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
>>> net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
>>> net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
>>> net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
>>> ...
>> Side effect of the git-net removal, temporarily removing 
>> immunize-rcu_dereference-against-crazy-compiler-writers.patch should 
>> work around it.
> 
> Alternatively, the following one-line patch to net/ipv4/fib_trie.c could
> be used.
> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> 
>  fib_trie.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -urpNa -X dontdiff linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c
> --- linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c	2007-08-22 09:20:33.000000000 -0700
> +++ linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c	2007-08-22 09:47:33.000000000 -0700
> @@ -94,7 +94,7 @@ typedef unsigned int t_key;
>  #define T_LEAF  1
>  #define NODE_TYPE_MASK	0x1UL
>  #define NODE_PARENT(node) \
> -	((struct tnode *)rcu_dereference(((node)->parent & ~NODE_TYPE_MASK)))
> +	((struct tnode *)(rcu_dereference((node)->parent) & ~NODE_TYPE_MASK))
...

After first reading of this thread I've had an impression it's about
compiler's behavior, but now it seems to me this patch is not an
alternative, but a 'must be' and only proper way of calling
rcu_dereference (with a variable instead of an expression)? Am I
right?

Regards,
Jarek P.

Re: net/ipv4/fib_trie.c - compile error (Re: 2.6.23-rc3-mm1)

[Paul E. McKenney]

On Mon, Aug 27, 2007 at 08:36:35AM +0200, Jarek Poplawski wrote:
> On 22-08-2007 19:03, Paul E. McKenney wrote:
> > On Wed, Aug 22, 2007 at 05:41:11PM +0200, Adrian Bunk wrote:
> >> On Wed, Aug 22, 2007 at 05:30:13PM +0200, Gabriel C wrote:
> >>> Got it with a randconfig ( http://194.231.229.228/kernel/mm/2.6.23-rc3-mm1/r/randconfig-8 )
> >>>
> >>> ...
> >>>
> >>> net/ipv4/fib_trie.c: In function 'trie_rebalance':
> >>> net/ipv4/fib_trie.c:969: error: lvalue required as unary '&' operand
> >>> net/ipv4/fib_trie.c:971: error: lvalue required as unary '&' operand
> >>> net/ipv4/fib_trie.c:977: error: lvalue required as unary '&' operand
> >>> net/ipv4/fib_trie.c:980: error: lvalue required as unary '&' operand
> >>> ...
> >> Side effect of the git-net removal, temporarily removing 
> >> immunize-rcu_dereference-against-crazy-compiler-writers.patch should 
> >> work around it.
> > 
> > Alternatively, the following one-line patch to net/ipv4/fib_trie.c could
> > be used.
> > 
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > ---
> > 
> >  fib_trie.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff -urpNa -X dontdiff linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c
> > --- linux-2.6.23-rc3-mm1/net/ipv4/fib_trie.c	2007-08-22 09:20:33.000000000 -0700
> > +++ linux-2.6.23-rc3-mm1.compile/net/ipv4/fib_trie.c	2007-08-22 09:47:33.000000000 -0700
> > @@ -94,7 +94,7 @@ typedef unsigned int t_key;
> >  #define T_LEAF  1
> >  #define NODE_TYPE_MASK	0x1UL
> >  #define NODE_PARENT(node) \
> > -	((struct tnode *)rcu_dereference(((node)->parent & ~NODE_TYPE_MASK)))
> > +	((struct tnode *)(rcu_dereference((node)->parent) & ~NODE_TYPE_MASK))
> ...
> 
> After first reading of this thread I've had an impression it's about
> compiler's behavior, but now it seems to me this patch is not an
> alternative, but a 'must be' and only proper way of calling
> rcu_dereference (with a variable instead of an expression)? Am I
> right?

Yes, rcu_dereference() does indeed need to be invoked on a lvalue.

							Thanx, Paul