[Bug translator/19358] New: netfilter probes are broken on rawhide

[Bug translator/19358] New: netfilter probes are broken on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=19358

            Bug ID: 19358
           Summary: netfilter probes are broken on rawhide
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: translator
          Assignee: systemtap at sourceware dot org
          Reporter: dsmith at redhat dot com
  Target Milestone: ---

Netfilter probes appear to have compilation problems on rawhide
(4.4.0-0.rc3.git4.1.fc24.x86_64):

=====
# stap -g -p4 ../src/testsuite/systemtap.examples/network/netfilter_drop.stp
TCP 1
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:2519:9:
error: initialization from incompatible pointer type
[-Werror=incompatible-pointer-types]
 .hook = enter_netfilter_probe_0,
         ^
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:2519:9: note:
(near initialization for ‘netfilter_opts_0.hook’)
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:2520:1:
error: unknown field ‘owner’ specified in initializer
 .owner = THIS_MODULE,
 ^
In file included from include/linux/linkage.h:6:0,
                 from include/linux/preempt.h:9,
                 from include/linux/spinlock.h:50,
                 from include/linux/mmzone.h:7,
                 from include/linux/gfp.h:5,
                 from
/usr/local/share/systemtap/runtime/linux/runtime_defines.h:20,
                 from /usr/local/share/systemtap/runtime/runtime_defines.h:8,
                 from
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:10:
include/linux/export.h:34:21: error: initialization from incompatible pointer
type [-Werror=incompatible-pointer-types]
 #define THIS_MODULE (&__this_module)
                     ^
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:2520:10:
note: in expansion of macro ‘THIS_MODULE’
 .owner = THIS_MODULE,
          ^
include/linux/export.h:34:21: note: (near initialization for
‘netfilter_opts_0.dev’)
 #define THIS_MODULE (&__this_module)
                     ^
/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.c:2520:10:
note: in expansion of macro ‘THIS_MODULE’
 .owner = THIS_MODULE,
          ^
cc1: all warnings being treated as errors
scripts/Makefile.build:258: recipe for target
'/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.o' failed
make[1]: ***
[/tmp/stapKszyjv/stap_638ac27ca43bafef41a50ed201d5c6bd_19005_src.o] Error 1
Makefile:1388: recipe for target '_module_/tmp/stapKszyjv' failed
make: *** [_module_/tmp/stapKszyjv] Error 2
WARNING: kbuild exited with status: 2
Pass 4: compilation failed.  [man error::pass4]
=====

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[Bug translator/19358] netfilter probes are broken on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=19358

--- Comment #1 from David Smith <dsmith at redhat dot com> ---
It looks like the following kernel commit got rid of the 'owner' field:

====
ommit 2ffbceb2b08f8ca0496c54a9ebcd11d25275954e                                 
Author: Florian Westphal <fw@strlen.de>                                         
Date:   Tue Oct 13 14:33:26 2015 +0200                                          

    netfilter: remove hook owner refcounting                                    

    since commit 8405a8fff3f8 ("netfilter: nf_qeueue: Drop queue entries on     
    nf_unregister_hook") all pending queued entries are discarded.              

    So we can simply remove all of the owner handling -- when module is         
    removed it also needs to unregister all its hooks.                          
====

It looks like the following kernel commit changed the 'hook' field:

====
commit 008027c31d57a22bd80dda5acc95b037634eee0f                                 
Author: Arnd Bergmann <arnd@arndb.de>                                           
Date:   Fri Oct 9 20:45:42 2015 +0200                                           

    netfilter: turn NF_HOOK into an inline function                             

    A recent change to the dst_output handling caused a new warning             
    when the call to NF_HOOK() is the only used of a local variable             
    passed as 'dev', and CONFIG_NETFILTER is disabled:                          

    net/ipv6/ip6_output.c: In function 'ip6_output':                            
    net/ipv6/ip6_output.c:135:21: warning: unused variable 'dev'
[-Wunused-vari\
able]                                                                           

    The reason for this is that the NF_HOOK macro in this case does             
    not reference the variable at all, and the call to dev_net(dev)             
    got removed from the ip6_output function. To avoid that warning now         
    and in the future, this changes the macro into an equivalent                
    inline function, which tells the compiler that the variable is              
    passed correctly but still unused.                                          

    The dn_forward function apparently had the same problem in                  
    the past and added a local workaround that no longer works                  
    with the inline function. In order to avoid a regression, we                
    have to also remove the #ifdef from decnet in the same patch.               
====

It looks like these changes first appeared in kernel v4.4-rc1.

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[Bug translator/19358] netfilter probes are broken on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=19358

--- Comment #2 from David Smith <dsmith at redhat dot com> ---
Here's another related kernel commit that changed the netfilter hook function
signature:

====
commit 06198b34a3e09e06d9aecaa3727e0d37206cea77
Author: Eric W. Biederman <ebiederm@xmission.com>
Date:   Fri Sep 18 14:33:06 2015 -0500

    netfilter: Pass priv instead of nf_hook_ops to netfilter hooks

    Only pass the void *priv parameter out of the nf_hook_ops.  That is
    all any of the functions are interested now, and by limiting what is
    passed it becomes simpler to change implementation details.

    Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
    Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
====

It looks like this change first appeared in kernel v4.4-rc1.

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[Bug translator/19358] netfilter probes are broken on rawhide

[dsmith at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=19358

David Smith <dsmith at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from David Smith <dsmith at redhat dot com> ---
Fixed in commit 2736131.

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