[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5] Fixes to Xen pciback for 3.17.
Greg: goto GHK This is v5 version of patches to fix some issues in Xen PCIback. One of the issues Xen PCI back has that patch: is fixing is that a deadlock can happen if the PCI device is assigned to a guest and we try to 'unbind' it from Xen 'pciback' driver. The issue is rather simple - the SysFS mechanism for the 'unbind' path takes a device lock and the code in Xen PCI uses the pci_reset_function which also takes the same lock. Solution is to use the lock-less version and mandate that callers of said function in Xen pciback take the lock. Easy enough. GHK: To guard against this happening in the future we also add an assert in the form of lockdep assertion. That is OK except that it looks ugly as we take it straight from the 'struct device' instead of using an appropriate macro. See: + lockdep_assert_held(&dev->dev.mutex); (in [PATCH v5 2/6] xen/pciback: Don't deadlock when unbinding). The patch: [PATCH v5 3/6] driver core: Provide an wrapper around the mutex to do. introduces a nice wrapper so it is bit cleaner. Greg, if you are OK with it could you kindly Ack it as I would prefer to put this patchset via the Xen tree. It would look now as: - lockdep_assert_held(&dev->dev.mutex); + device_lock_assert(&dev->dev); I can also squash it in "[PATCH v5 2/6] xen/pciback: Don't deadlock when unbinding." but since that one is going through the stable tree I wasn't sure whether you (Greg KH) would be OK with that. END GHK: Thank you! Patches are also available on my git tree git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git devel/pciback-3.17.v5 Documentation/ABI/testing/sysfs-driver-pciback | 25 +++++++++++++++ drivers/xen/xen-pciback/passthrough.c | 14 +++++++-- drivers/xen/xen-pciback/pci_stub.c | 42 ++++++++++++++------------ drivers/xen/xen-pciback/pciback.h | 7 +++-- drivers/xen/xen-pciback/vpci.c | 14 +++++++-- drivers/xen/xen-pciback/xenbus.c | 4 +-- include/linux/device.h | 5 +++ 7 files changed, 81 insertions(+), 30 deletions(-) Konrad Rzeszutek Wilk (6): xen-pciback: Document the various parameters and attributes in SysFS xen/pciback: Don't deadlock when unbinding. driver core: Provide an wrapper around the mutex to do lockdep warnings xen/pciback: Include the domain id if removing the device whilst still in use xen/pciback: Print out the domain owning the device. xen/pciback: Remove tons of dereferences _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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