Messages in this thread | | | From | Tong Zhang <> | Date | Fri, 14 Aug 2020 11:37:20 -0400 | Subject | Re: [PATCH] nvme-pci: cancel nvme device request before disabling |
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Hi Keith,
On Fri, Aug 14, 2020 at 11:04 AM Keith Busch <kbusch@kernel.org> wrote: > > On Fri, Aug 14, 2020 at 03:14:31AM -0400, Tong Zhang wrote: > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > > index ba725ae47305..c4f1ce0ee1e3 100644 > > --- a/drivers/nvme/host/pci.c > > +++ b/drivers/nvme/host/pci.c > > @@ -1249,8 +1249,8 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved) > > dev_warn_ratelimited(dev->ctrl.device, > > "I/O %d QID %d timeout, disable controller\n", > > req->tag, nvmeq->qid); > > - nvme_dev_disable(dev, true); > > nvme_req(req)->flags |= NVME_REQ_CANCELLED; > > + nvme_dev_disable(dev, true); > > return BLK_EH_DONE; > > Shouldn't this flag have been set in nvme_cancel_request()?
nvme_cancel_request() is not setting this flag to cancelled and this is causing __nvme_submit_sync_cmd() to return a positive number and eventually this will allow nvme_init_identify() proceed with a timeout error where the problematic nvme device has already been disabled by nvme_dev_disable(dev,true). The reset of the logic in nvme_init_identify() is not going to check those already released resources. -- in fact this is UAF --
> like the timeout out command is the only command to have been cancelled > by this action, nor is it guaranteed that getting here will mean the > request was in fact cancelled. The controller could still provide a real > completion.
what would you like to suggest here?
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