Re: pci: endpoint test BUG

[Lorenzo Pieralisi]

On Tue, Sep 17, 2019 at 11:10:37AM +0530, Kishon Vijay Abraham I wrote:
> 
> On 16/09/19 4:52 PM, Lorenzo Pieralisi wrote:
> > On Mon, Sep 16, 2019 at 10:06:30AM +0800, Hillf Danton wrote:
> >>
> >> On Sun, 15 Sep 2019 09:34:37 -0700
> >>>
> >>> Kernel is 5.3-rc8 on x86_64.
> >>>
> >>> Loading and removing the pci-epf-test module causes a BUG.
> >>>
> >>>
> >>> [40928.435755] calling  pci_epf_test_init+0x0/0x1000 [pci_epf_test] @ 12132
> >>> [40928.436717] initcall pci_epf_test_init+0x0/0x1000 [pci_epf_test] returned 0 after 891 usecs
> >>> [40936.996081] ==================================================================
> >>> [40936.996125] BUG: KASAN: use-after-free in pci_epf_remove_cfs+0x1ae/0x1f0
> >>> [40936.996153] Write of size 8 at addr ffff88810a22a068 by task rmmod/12139
> >>
> >> Fix fb0de5b8dcc6 and ef1433f717a2 if the current group::group_entry
> >> used by pci epf does not break how configfs uses it.
> >>
> >> --- a/drivers/pci/endpoint/pci-epf-core.c
> >> +++ b/drivers/pci/endpoint/pci-epf-core.c
> >> @@ -153,9 +153,11 @@ static void pci_epf_remove_cfs(struct pc
> >>  		return;
> >>  
> >>  	mutex_lock(&pci_epf_mutex);
> >> -	list_for_each_entry_safe(group, tmp, &driver->epf_group, group_entry)
> >> +	list_for_each_entry_safe(group, tmp, &driver->epf_group,
> >> +							group_entry) {
> >> +		list_del_init(&group->group_entry);
> >>  		pci_ep_cfs_remove_epf_group(group);
> >> -	list_del(&driver->epf_group);
> >> +	}
> >>  	mutex_unlock(&pci_epf_mutex);
> >>  }
> 
> 
> Acked-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> 
> > 
> > Thank you Hillf. Kishon, can you confirm that's the proper fix for
> > this bug please ? I would like to turn this into a patch and merge
> > it in the upcoming merge window PR so it ought to be fairly quick,
> > please let me know asap.

Kishon, Hillf, can you turn it into a patch and send it asap please ?

Thanks,
Lorenzo