Messages in this thread | | | Date | Mon, 28 Oct 2013 18:30:56 +0100 | From | Veaceslav Falico <> | Subject | Re: [BUG 3.12.rc4] Oops: unable to handle kernel paging request during shutdown |
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On Mon, Oct 28, 2013 at 11:23:41AM -0600, Bjorn Helgaas wrote: >[+cc Veaceslav] > >On Sun, Oct 27, 2013 at 3:24 PM, Greg Kroah-Hartman ><gregkh@linuxfoundation.org> wrote: >> On Sun, Oct 27, 2013 at 09:13:29PM +0000, Linus Torvalds wrote: >>> .. and one more case of freeing a delayed work object (likely a kobject again): >>> >>> This time it looks like it's in the PCI layer, freeing the msi irq information. >>> >>> It looks like that code simply does >>> >>> kobject_del(&entry->kobj); >>> kobject_put(&entry->kobj); >>> list_del(&entry->list); >>> kfree(entry); >>> >>> and the problem is that the "entry->kobj" may have *other* references >>> to it, thanks to people accessing it through /sys, so despite doing a >>> kojbect_del/kobject_put(), it's not at all ok to then do a "kfree()" >>> on it. The embedded kobj might still be in use. >>> >>> Afaik, that code should do the kfree() on the kobject in the _release_ >>> method, not synchronously like that. >>> >>> We already have a msi_kobj_release(), I'm wondering why that doesn't >>> do the kfree(). >>> >>> Bjorn? Yinghai? Greg, comments about that msi kobj usage? >> >> Ick, it really should be doing a kfree() in the release only. Bjorn has >> had a bunch of changes in this area recently, perhaps they are in >> linux-next waiting for 3.13, and I've talked to him about getting rid of >> all of the kobjects for msi files, as I don't think it's needed at all. > >IIRC, you said you might take a look at converting this to attributes >on the train back home, so I haven't looked into it myself :) > >> Bjorn, don't you have a fix for this problem already done somewhere? > >Yep, this is clearly wrong, and Veaceslav has a patch that moves the >kfree() to the release function. I've been waiting for a consolidated >repost of all his MSI-related fixes, but maybe he's been waiting for >*me*.
https://lkml.org/lkml/2013/10/9/170
My patchset is ready to be applied, in its v2 state.
Except that the bits with kobject_del() (theoretical race) - which are done in your patch "kobject: remove kset from sysfs immediately in kset_unregister()", though I didn't see it accepted.
Should I re-send the patchset?
> >Bjorn
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