[dpdk-dev] [PATCH 2/2] but/pci: fix fd close for hot-unplug

[Jeff Guo]

When device is hot-unplugged, the device fd will be deleted in kernel.
Then in the progress of detaching device, if it try to close the fd,
it will cause a kernel crash, which shown a kernel null pointer error.

This patch aim to fix this issue by checking the device state to decide
whether the fd need to be closed or not.

Fixes: 5a60a7ffc801 ("pci: introduce functions to alloc and free uio resource")
Fixes: 9b957f378abf ("pci: merge uio functions for linux and bsd")
Fixes: 0fc54536b14a ("eal: add failure handling for hot-unplug")
Signed-off-by: Jeff Guo <jia.guo at intel.com>
---
 drivers/bus/pci/linux/pci_uio.c       |  3 +++
 drivers/bus/pci/pci_common_uio.c      | 16 +++++++++-------
 lib/librte_eal/linuxapp/eal/eal_dev.c |  1 +
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index a7c1442..7844ed4 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -199,6 +199,9 @@ pci_uio_free_resource(struct rte_pci_device *dev,
 {
 	rte_free(uio_res);
 
+	if (dev->device.state == RTE_DEV_REMOVED)
+		return;
+
 	if (dev->intr_handle.uio_cfg_fd >= 0) {
 		close(dev->intr_handle.uio_cfg_fd);
 		dev->intr_handle.uio_cfg_fd = -1;
diff --git a/drivers/bus/pci/pci_common_uio.c b/drivers/bus/pci/pci_common_uio.c
index 7ea73db..bc329b5 100644
--- a/drivers/bus/pci/pci_common_uio.c
+++ b/drivers/bus/pci/pci_common_uio.c
@@ -227,12 +227,14 @@ pci_uio_unmap_resource(struct rte_pci_device *dev)
 	rte_free(uio_res);
 
 	/* close fd if in primary process */
-	close(dev->intr_handle.fd);
-	if (dev->intr_handle.uio_cfg_fd >= 0) {
-		close(dev->intr_handle.uio_cfg_fd);
-		dev->intr_handle.uio_cfg_fd = -1;
-	}
+	if (dev->device.state != RTE_DEV_REMOVED && dev->intr_handle.fd >= 0) {
+		close(dev->intr_handle.fd);
+		if (dev->intr_handle.uio_cfg_fd >= 0) {
+			close(dev->intr_handle.uio_cfg_fd);
+			dev->intr_handle.uio_cfg_fd = -1;
+		}
 
-	dev->intr_handle.fd = -1;
-	dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;
+		dev->intr_handle.fd = -1;
+		dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN;
+	}
 }
diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c b/lib/librte_eal/linuxapp/eal/eal_dev.c
index 2830c86..030e639 100644
--- a/lib/librte_eal/linuxapp/eal/eal_dev.c
+++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
@@ -269,6 +269,7 @@ dev_uev_handler(__rte_unused void *param)
 				goto failure_handle_err;
 			}
 
+			dev->state = RTE_DEV_REMOVED;
 			ret = bus->hot_unplug_handler(dev);
 			if (ret) {
 				RTE_LOG(ERR, EAL, "Can not handle hot-unplug "
-- 
2.7.4