[+cc Veaceslav] On Sun, Oct 27, 2013 at 3:24 PM, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> 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*. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
