Hi John, CC robh
On Tue, Mar 26, 2019 at 12:42 PM John Garry <john.ga...@huawei.com> wrote: > > Memory is incorrectly freed using the direct ops, as dma_map_ops = NULL. > > Oops... > > > > After reversing the order of the calls to arch_teardown_dma_ops() and > > devres_release_all(), dma_map_ops is still valid, and the DMA memory is > > now released using __iommu_free_attrs(): > > > > +sata_rcar ee300000.sata: dmam_release:32: size 2048 vaddr > > ffffff8012145000 dma_handle 0x0x00000000fffff000 attrs 0x0 > > +sata_rcar ee300000.sata: dma_free_attrs:289: size 2048, ops = > > iommu_dma_ops > > +sata_rcar ee300000.sata: dma_free_attrs:311: calling > > __iommu_free_attrs() > > --- > > drivers/base/dd.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > index 8ac10af17c0043a3..d62487d024559620 100644 > > --- a/drivers/base/dd.c > > +++ b/drivers/base/dd.c > > @@ -968,9 +968,9 @@ static void __device_release_driver(struct device *dev, > > struct device *parent) > > drv->remove(dev); > > > > device_links_driver_cleanup(dev); > > - arch_teardown_dma_ops(dev); > > > > devres_release_all(dev); > > + arch_teardown_dma_ops(dev); > > dev->driver = NULL; > > Hi guys, > > Could there still be the same problem in the error path of really_probe(): > > static int really_probe(struct device *dev, struct device_driver *drv) > { > > [...] > > goto done; > > probe_failed: > arch_teardown_dma_ops(dev); > dma_failed: > if (dev->bus) > blocking_notifier_call_chain(&dev->bus->p->bus_notifier, > BUS_NOTIFY_DRIVER_NOT_BOUND, dev); > pinctrl_bind_failed: > device_links_no_driver(dev); > devres_release_all(dev); > driver_sysfs_remove(dev); > dev->driver = NULL; > dev_set_drvdata(dev, NULL); > > We seem to be able to call arch_teardown_dma_ops() prior to > devres_release_all() if we reach probe_failed label. Yes, this looks like another instance of the same problem. And test_remove doesn't expose this, as it doesn't exercise the full cycle. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds