| Message ID | 51B4B266.5010100@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Mon, Jun 10, 2013 at 12:50:46AM +0800, Jiang Liu wrote: > On Sat 08 Jun 2013 01:07:06 AM CST, Konrad Rzeszutek Wilk wrote: > > On Sat, Jun 08, 2013 at 12:50:31AM +0800, Jiang Liu wrote: > >> On 06/07/2013 11:38 PM, Konrad Rzeszutek Wilk wrote: > >>> On Fri, Jun 07, 2013 at 10:50:24AM -0400, Konrad Rzeszutek Wilk wrote: > >>>> On Thu, May 16, 2013 at 11:50:55PM +0800, Jiang Liu wrote: > >>>>> Use new PCI interfaces to simplify xen-pcifront implementation: > >>>>> 1) Use pci_create_root_bus() instead of pci_scan_bus_parented() > >>>>> because pci_scan_bus_parented() is marked as __deprecated.This > >>>>> also gets rid of a duplicated call of pci_bus_start_devices(). > >>>>> 2) Use pci_stop_root_bus() and pci_remove_root_bus() instead of > >>>>> open-coded private implementation. > >>>>> 3) Use pci_set_host_bridge_release() to release data structures > >>>>> associated with PCI root buses. > >>>>> 4) Use pci_bus_get()/pci_bus_put() to manage PCI root bus reference > >>>>> count. > >>>>> > >>>>> This is also a preparation for coming PCI bus lock enhancement. > >>> > >>> With this patch from : > >>> > >>> Merge branch 'pci_lock_v3' of https://github.com/jiangliu/linux into testing > >>> > >>> > >>> it blows up when detaching the device. > >> Hi Konrad, > >> Thanks for testing! According to the log messages, this issue should > >> be related to pci bus reference counter management. Seems we have done > >> an extra(unbalanced) release of pci bus device. > >> Will investigate it tomorrow! > > > > That is quite commendable that you are willing to look over this on > > the weekend but I am not going to be able to rerun this test until > > some time in the week. You could enjoy the weekend and just look at > > this during the week. > > Hi Konrad, > We should have root-caused this bug, which is caused by > for_each_pci_root_bus(). > Current implementation doesn't support root bus deletion when walking > PCI root > buses by for_each_pci_root_bus(). The reference counter > (pci_bus->dev.knode_class.n_ref) > becomes zero after returning from pci_remove_root_bus(), so it triggers > kref warnings > and double-free of klist_node object when we call > pci_get_next_root_bus() to get the > next PCI root bus. > So we will first revert to list_for_each_entry_safe(bus, temp, > &pci_root_buses, node) > and solve this issue in next version of for_each_pci_root_bus(). That definitly solves the issue. Thanks! I used pci_lock_v3 of https://github.com/jiangliu/linux and the fix below. Is there a new patchset you are going to be posting or a git branch that I can look over? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue 11 Jun 2013 12:58:01 AM CST, Konrad Rzeszutek Wilk wrote: > On Mon, Jun 10, 2013 at 12:50:46AM +0800, Jiang Liu wrote: >> On Sat 08 Jun 2013 01:07:06 AM CST, Konrad Rzeszutek Wilk wrote: >>> On Sat, Jun 08, 2013 at 12:50:31AM +0800, Jiang Liu wrote: >>>> On 06/07/2013 11:38 PM, Konrad Rzeszutek Wilk wrote: >>>>> On Fri, Jun 07, 2013 at 10:50:24AM -0400, Konrad Rzeszutek Wilk wrote: >>>>>> On Thu, May 16, 2013 at 11:50:55PM +0800, Jiang Liu wrote: >>>>>>> Use new PCI interfaces to simplify xen-pcifront implementation: >>>>>>> 1) Use pci_create_root_bus() instead of pci_scan_bus_parented() >>>>>>> because pci_scan_bus_parented() is marked as __deprecated.This >>>>>>> also gets rid of a duplicated call of pci_bus_start_devices(). >>>>>>> 2) Use pci_stop_root_bus() and pci_remove_root_bus() instead of >>>>>>> open-coded private implementation. >>>>>>> 3) Use pci_set_host_bridge_release() to release data structures >>>>>>> associated with PCI root buses. >>>>>>> 4) Use pci_bus_get()/pci_bus_put() to manage PCI root bus reference >>>>>>> count. >>>>>>> >>>>>>> This is also a preparation for coming PCI bus lock enhancement. >>>>> >>>>> With this patch from : >>>>> >>>>> Merge branch 'pci_lock_v3' of https://github.com/jiangliu/linux into testing >>>>> >>>>> >>>>> it blows up when detaching the device. >>>> Hi Konrad, >>>> Thanks for testing! According to the log messages, this issue should >>>> be related to pci bus reference counter management. Seems we have done >>>> an extra(unbalanced) release of pci bus device. >>>> Will investigate it tomorrow! >>> >>> That is quite commendable that you are willing to look over this on >>> the weekend but I am not going to be able to rerun this test until >>> some time in the week. You could enjoy the weekend and just look at >>> this during the week. >> >> Hi Konrad, >> We should have root-caused this bug, which is caused by >> for_each_pci_root_bus(). >> Current implementation doesn't support root bus deletion when walking >> PCI root >> buses by for_each_pci_root_bus(). The reference counter >> (pci_bus->dev.knode_class.n_ref) >> becomes zero after returning from pci_remove_root_bus(), so it triggers >> kref warnings >> and double-free of klist_node object when we call >> pci_get_next_root_bus() to get the >> next PCI root bus. >> So we will first revert to list_for_each_entry_safe(bus, temp, >> &pci_root_buses, node) >> and solve this issue in next version of for_each_pci_root_bus(). > > That definitly solves the issue. Thanks! > > I used pci_lock_v3 of https://github.com/jiangliu/linux and the fix > below. > > Is there a new patchset you are going to be posting or a git branch > that I can look over? > > Thanks. Hi Konrad, Really appreciate your support! I will try to post a new version tomorrow, but I think there won't be big changes except addressing some review comments from you. Thanks! Gerry -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jun 11, 2013 at 01:08:14AM +0800, Jiang Liu wrote: > On Tue 11 Jun 2013 12:58:01 AM CST, Konrad Rzeszutek Wilk wrote: > > On Mon, Jun 10, 2013 at 12:50:46AM +0800, Jiang Liu wrote: > >> On Sat 08 Jun 2013 01:07:06 AM CST, Konrad Rzeszutek Wilk wrote: > >>> On Sat, Jun 08, 2013 at 12:50:31AM +0800, Jiang Liu wrote: > >>>> On 06/07/2013 11:38 PM, Konrad Rzeszutek Wilk wrote: > >>>>> On Fri, Jun 07, 2013 at 10:50:24AM -0400, Konrad Rzeszutek Wilk wrote: > >>>>>> On Thu, May 16, 2013 at 11:50:55PM +0800, Jiang Liu wrote: > >>>>>>> Use new PCI interfaces to simplify xen-pcifront implementation: > >>>>>>> 1) Use pci_create_root_bus() instead of pci_scan_bus_parented() > >>>>>>> because pci_scan_bus_parented() is marked as __deprecated.This > >>>>>>> also gets rid of a duplicated call of pci_bus_start_devices(). > >>>>>>> 2) Use pci_stop_root_bus() and pci_remove_root_bus() instead of > >>>>>>> open-coded private implementation. > >>>>>>> 3) Use pci_set_host_bridge_release() to release data structures > >>>>>>> associated with PCI root buses. > >>>>>>> 4) Use pci_bus_get()/pci_bus_put() to manage PCI root bus reference > >>>>>>> count. > >>>>>>> > >>>>>>> This is also a preparation for coming PCI bus lock enhancement. > >>>>> > >>>>> With this patch from : > >>>>> > >>>>> Merge branch 'pci_lock_v3' of https://github.com/jiangliu/linux into testing > >>>>> > >>>>> > >>>>> it blows up when detaching the device. > >>>> Hi Konrad, > >>>> Thanks for testing! According to the log messages, this issue should > >>>> be related to pci bus reference counter management. Seems we have done > >>>> an extra(unbalanced) release of pci bus device. > >>>> Will investigate it tomorrow! > >>> > >>> That is quite commendable that you are willing to look over this on > >>> the weekend but I am not going to be able to rerun this test until > >>> some time in the week. You could enjoy the weekend and just look at > >>> this during the week. > >> > >> Hi Konrad, > >> We should have root-caused this bug, which is caused by > >> for_each_pci_root_bus(). > >> Current implementation doesn't support root bus deletion when walking > >> PCI root > >> buses by for_each_pci_root_bus(). The reference counter > >> (pci_bus->dev.knode_class.n_ref) > >> becomes zero after returning from pci_remove_root_bus(), so it triggers > >> kref warnings > >> and double-free of klist_node object when we call > >> pci_get_next_root_bus() to get the > >> next PCI root bus. > >> So we will first revert to list_for_each_entry_safe(bus, temp, > >> &pci_root_buses, node) > >> and solve this issue in next version of for_each_pci_root_bus(). > > > > That definitly solves the issue. Thanks! > > > > I used pci_lock_v3 of https://github.com/jiangliu/linux and the fix > > below. > > > > Is there a new patchset you are going to be posting or a git branch > > that I can look over? > > > > Thanks. > Hi Konrad, > Really appreciate your support! I will try to post a new version > tomorrow, > but I think there won't be big changes except addressing some review > comments from you. I also get this: ERROR: "pci_set_host_bridge_release" [drivers/pci/xen-pcifront.ko] undefined! ERROR: "pci_create_root_bus" [drivers/pci/xen-pcifront.ko] undefined! ERROR: "pci_remove_root_bus" [drivers/pci/xen-pcifront.ko] undefined! ERROR: "pci_stop_root_bus" [drivers/pci/xen-pcifront.ko] undefined! when building it as a module. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c index 6aa2c0f..6e577db 100644 --- a/drivers/pci/xen-pcifront.c +++ b/drivers/pci/xen-pcifront.c @@ -553,11 +553,11 @@ static int pcifront_rescan_root(struct pcifront_device *pdev, static void pcifront_free_roots(struct pcifront_device *pdev) { struct pcifront_sd *sd; - struct pci_bus *bus; + struct pci_bus *bus, *temp; dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n"); - for_each_pci_root_bus(bus) { + list_for_each_entry_safe(bus, temp, &pci_root_buses, node) { sd = bus->sysdata; if (sd->pdev == pdev) {