Re: [broken-out-2007-07-20-00-22] kernel bug at kernel/params:570

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



[ Considering this has sufficiently excited me, I became the second person
to illegitimately download 2.6.22-mm1 and am presently building Michal's
config. The strange thing is that I couldn't get 22-mm1 to even build with
the posted .config -- so had to deselect XFS, ATA, unionfs.

Hopefully this bug should be 100% reproducible at boot time anyway.
Don't care much for XFS and unionfs, but hoping deselecting ATA from
the config doesn't change the variables much in this equation. ]


On 7/21/07, Greg KH <[email protected]> wrote:
On Fri, Jul 20, 2007 at 06:37:33PM -0700, Andrew Morton wrote:
> On Fri, 20 Jul 2007 18:02:57 -0700 Greg KH <[email protected]> wrote:
>
> > --- a/kernel/params.c
> > +++ b/kernel/params.c
> > @@ -567,7 +567,11 @@ static void __init kernel_param_sysfs_se
> >     kobject_set_name(&mk->kobj, name);
> >     kobject_init(&mk->kobj);
> >     ret = kobject_add(&mk->kobj);
> > -   BUG_ON(ret < 0);
> > +   if (ret) {
> > +           printk(KERN_ERR "module '%s' failed to be added to sysfs, "
> > +                   "the system will be unstable now.\n", name);
> > +           return;
> > +   }
>
> It would be nice to print the value of `ret' too.


What I'm surprised about is that %eax doesn't seem to contain the
return value `ret' of kobject_add(). It's 1, which is funny, given:

ret = kobject_add(&mk->kobj);
BUG_ON(ret < 0);

One wouldn't expect BUG() -- or the corresponding exception handler --
to clobber registers, that would be a sad day.


Ok, how about this version:

---
 kernel/params.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--- a/kernel/params.c
+++ b/kernel/params.c
@@ -567,7 +567,12 @@ static void __init kernel_param_sysfs_se
        kobject_set_name(&mk->kobj, name);
        kobject_init(&mk->kobj);
        ret = kobject_add(&mk->kobj);
-       BUG_ON(ret < 0);
+       if (ret) {
+               printk(KERN_ERR "Module '%s' failed to be added to sysfs, "
+                     "error number %d\n", name, ret);
+               printk(KERN_ERR "The system will be unstable now.\n");
+               return;
+       }
        param_sysfs_setup(mk, kparam, num_params, name_skip);
        kobject_uevent(&mk->kobj, KOBJ_ADD);
 }


I'm building with this:

if (ret) {
       printk("~~~~~ .%s.%d.%s. ~~~~~\n", name, ret, kparam->name);
       return;
}

To also print out the evil kparam->name that caused us to crash.
When ret == EINVAL, name would be "", so not so helpful alone.

Also enabling netconsole, though I'm sure there's zero chances
of NET / ethXXX / netconsole being up _this_ early in the boot ...

Will keep you guys posted :-)

Satyam
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux