Messages in this thread | | | Date | Sat, 21 Jul 2007 05:13:12 +0530 | From | "Satyam Sharma" <> | Subject | Re: [broken-out-2007-07-20-00-22] kernel bug at kernel/params:570 |
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On 7/21/07, Greg KH <gregkh@suse.de> wrote: > On Fri, Jul 20, 2007 at 03:59:12PM -0700, Andrew Morton wrote: > > On Fri, 20 Jul 2007 15:50:47 -0700 > > Greg KH <gregkh@suse.de> wrote: > > > > > On Fri, Jul 20, 2007 at 06:32:21PM +0200, Michal Piotrowski wrote: > > > > Hi Greg, > > > > > > > > This looks like a sysfs bug > > > > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/ > > > > broken-out-2007-07-20-00-22/00003.jpg > > > > > > > > l *kernel_param_sysfs_setup+0x75 > > > > 0xc13c0894 is in kernel_param_sysfs_setup (kernel/params.c:570). > > > > 565 mk->mod = THIS_MODULE; > > > > 566 kobj_set_kset_s(mk, module_subsys); > > > > 567 kobject_set_name(&mk->kobj, name); > > > > 568 kobject_init(&mk->kobj); > > > > 569 ret = kobject_add(&mk->kobj); > > > > 570 BUG_ON(ret < 0); > > > > 571 param_sysfs_setup(mk, kparam, num_params, name_skip); > > > > 572 kobject_uevent(&mk->kobj, KOBJ_ADD); > > > > 573 } > > > > 574 > > > > > > > > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/broken-out-2007-07-20-00-22/mm-config > > > > > > What kernel version is this happening on? The -mm tree? Can you try > > > Linus's tree instead? > > > > > > It looks like there was some needed information right before the first > > > stack dump, showing exactly what kobject was trying to be added that was > > > already present. Odds are this is a kernel parameter with the same name > > > as a duplicate one within the same module,
I don't think that's an -EEXIST.
I think what we have here is kobject_add() exiting with -EINVAL. (kobject attempted to be registered with no name!)
[ The first trace on that screen shows: kobject_shadow_add+0x5b/0x189. That's the WARN_ON(1) at lib/kobject.c:176. If it was a EEXIST case, we would've seen an offset in kobject_shadow_add closer to 0x189, because the dump_stack() for EEXIST is barely 4 instructions before we return from that function. ]
> > > but the trick is going to be > > > trying to figure out what module is causing this.
So I'd guess we want to search for a module that's passing a kobject * to kobject_add() such that !kobj->k_name is true.
> > > So it's not a sysfs bug, but rather a driver issue that this is > > > catching. > > > > In that case a BUG was way too harsh treatment, and in fact directly > > contributed to our inability to debug the bug! > > > > Can we wind that back a bit? Add some useful printks and then recover > > in some fashion? > [...] > So I'm guessing he was trying to catch something specific here.
Considering that:
(1) This isn't a bug that should bring down the kernel that hard, and, (2) kobject_shadow_add() seems to be dumping enough stacks and printing printk's on errors already,
I'd suggest to just get rid of the BUG_ON() in kernel_param_sysfs_setup()
Satyam - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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