On Tue, Sep 18, 2018 at 3:15 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > [+cc Christoph] > > On Sun, Sep 09, 2018 at 04:26:37PM +0800, Tonghao Zhang wrote: > > Hi all, > > When I enable pci msi or msix more than once, the kernel will panic. > > Now we just use the WARN_ON, should we add check for that has been > > enabled. > > > > This needs a signed-off-by before I can apply it. See > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst#n416 OK > A WARN_ON() shouldn't cause the kernel to panic. Do you mean that it > causes a backtrace? I think that's the intended behavior, because > calling this twice would be a driver bug, and we want to find and fix > those bugs. Yes, you are right, but we can return error code when drivers call this twice. > > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c > > index f2ef896..324840f 100644 > > --- a/drivers/pci/msi.c > > +++ b/drivers/pci/msi.c > > @@ -958,7 +958,9 @@ static int __pci_enable_msix(struct pci_dev *dev, > > struct msix_entry *entries, > > } > > } > > } > > - WARN_ON(!!dev->msix_enabled); > > + > > + if (dev->msix_enabled) > > + return -EINVAL; > > > > /* Check whether driver already requested for MSI irq */ > > if (dev->msi_enabled) { > > @@ -1028,7 +1030,8 @@ static int __pci_enable_msi_range(struct pci_dev > > *dev, int minvec, int maxvec, > > if (!pci_msi_supported(dev, minvec)) > > return -EINVAL; > > > > - WARN_ON(!!dev->msi_enabled); > > + if (dev->msi_enabled) > > + return -EINVAL; > > > > /* Check whether driver already requested MSI-X irqs */ > > if (dev->msix_enabled) {
