Re: crash failure with 2.6.36-rc3 vmcore

[caiqian@redhat.com]

Sorry for the confusion. Here is some background. The test here was to use the crash utility to analyse a vmcore generated from kdump. This commit caused its subcommand mod -S failed to gather the module section data from the in-kernel data structure as it looks like it still depends on this field. I am not sure if that the crash utility just need to be adjusted to cope with this kernel change.

>From http://people.redhat.com/anderson/crash_sources/symbols.c
/*
 *  Gather the module section data from the in-kernel data structures.
 */
static int
add_symbol_file_kallsyms(struct load_module *lm, struct gnu_request *req)
{
        int len, buflen, done, nsections, retval;
        ulong vaddr, array_entry, attribute, owner, name, address;
        long name_type;
        char buf[BUFSIZE];
        char section_name[BUFSIZE];
        ulong section_vaddr;

        if (!(st->flags & (MODSECT_V1|MODSECT_V2|MODSECT_V3|MODSECT_UNKNOWN))) {
                STRUCT_SIZE_INIT(module_sect_attr, "module_sect_attr");
                MEMBER_OFFSET_INIT(module_sect_attrs,
                        "module", "sect_attrs");
                MEMBER_OFFSET_INIT(module_sect_attrs_attrs,
                        "module_sect_attrs", "attrs");
                MEMBER_OFFSET_INIT(module_sect_attrs_nsections,
                        "module_sect_attrs", "nsections");
                MEMBER_OFFSET_INIT(module_sect_attr_mattr,
                        "module_sect_attr", "mattr");
                MEMBER_OFFSET_INIT(module_sect_attr_name,
                        "module_sect_attr", "name");
                MEMBER_OFFSET_INIT(module_sect_attr_address,
                        "module_sect_attr", "address");
                MEMBER_OFFSET_INIT(module_attribute_attr,
                        "module_attribute", "attr");
                MEMBER_OFFSET_INIT(module_sect_attr_attr,
                        "module_sect_attr", "attr");
                MEMBER_OFFSET_INIT(module_sections_attrs,
                        "module_sections", "attrs");
                MEMBER_OFFSET_INIT(attribute_owner,
                        "attribute", "owner");
...
                owner = attribute + OFFSET(attribute_owner);


----- "Guenter Roeck" <guenter.roeck@ericsson.com> wrote:

> Hi,
> 
> On Sat, Sep 04, 2010 at 02:01:06AM -0400, CAI Qian wrote:
> > 
> > > crash> mod -S
> > > 
> > > mod: invalid structure member offset: attribute_owner
> > >      FILE: symbols.c  LINE: 8577  FUNCTION:
> add_symbol_file_kallsyms()
> > > 
> > >      MODULE       NAME                   SIZE  OBJECT FILE
> > > ffffffffa000de60  dm_mod                76230 
> > >
> /lib/modules/2.6.36-rc2-mm1-wqfix-mkdfix+/kernel/drivers/md/dm-mod.ko
> > > [/usr/bin/crash] error trace: 4affb0 => 4f3236 => 4f12b5 =>
> 4e587a
> > > 
> > >   4e587a: OFFSET_verify.clone.4+186
> > >   4f12b5: add_symbol_file+933
> > >   4f3236: load_module_symbols+566
> > >   4affb0: do_module_cmd+1264
> > > 
> > > mod: invalid structure member offset: attribute_owner
> > >      FILE: symbols.c  LINE: 8577  FUNCTION:
> add_symbol_file_kallsyms()
> 
> What do I have to do to reproduce this crash ? 
> 
> Was the module in question compiled w/ the kernel, or separately ?
> Did it use the correct kernel header files for compilation ?
> Was the kernel version -rc3, or some other patched version ?
> 
> Just wondering, since the above message says
> 2.6.36-rc2-mm1-wqfix-mkdfix+,
> which seems to indicate that it included some modifications.
> 
> Thanks,
> Guenter
> 
> > This failure was due to this commit,
> > 
> > commit 6fd69dc578fa0b1bbc3aad70ae3af9a137211707
> > Author: Guenter Roeck <guenter.roeck@ericsson.com>
> > Date:   Wed Jul 28 22:09:26 2010 -0700
> > 
> >     sysfs: Remove owner field from sysfs struct attribute
> >     
> >     Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> >     Acked-by: Tejun Heo <tj@kernel.org>
> >     Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> > 
> > diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> > index 8bf06b6..3c92121 100644
> > --- a/include/linux/sysfs.h
> > +++ b/include/linux/sysfs.h
> > @@ -22,14 +22,8 @@ struct kobject;
> >  struct module;
> >  enum kobj_ns_type;
> >  
> > -/* FIXME
> > - * The *owner field is no longer used.
> > - * x86 tree has been cleaned up. The owner
> > - * attribute is still left for other arches.
> > - */
> >  struct attribute {
> >         const char              *name;
> > -       struct module           *owner;
> >         mode_t                  mode;
> >  #ifdef CONFIG_DEBUG_LOCK_ALLOC
> >         struct lock_class_key   *key;