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* [PATCH v2] pci: add O_CLOEXEC when open uio device
@ 2023-06-29  2:53 Weifeng Su
  2023-07-06 20:04 ` Stephen Hemminger
  0 siblings, 1 reply; 2+ messages in thread
From: Weifeng Su @ 2023-06-29  2:53 UTC (permalink / raw)
  To: dev; +Cc: stable, linfeilong, Weifeng Su

In this scenario, the DPDK process invokes a script which
inherits an open file descriptor (FD) for a UIO device.
After the script execution is complete, the UIO device's
close operation is called. However, in a new kernel version
(865a11f987ab5f03:uio/uio_pci_generic: Disable bus-mastering on release),
this close operation causes the PCI bus master bit to be cleared,
rendering the device unusable and leading to unexpected behavior.

This modification was made to prevent the UIO device's FD
from being inherited by the child process.

Signed-off-by: Weifeng Su <suweifeng1@huawei.com>
---
 drivers/bus/pci/linux/pci_uio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index d52125e49b..7ac142c36e 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -246,7 +246,7 @@ pci_uio_alloc_resource(struct rte_pci_device *dev,
 	snprintf(devname, sizeof(devname), "/dev/uio%u", uio_num);
 
 	/* save fd if in primary process */
-	fd = open(devname, O_RDWR);
+	fd = open(devname, O_RDWR | O_CLOEXEC);
 	if (fd < 0) {
 		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
 			devname, strerror(errno));
-- 
2.18.0.windows.1


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH v2] pci: add O_CLOEXEC when open uio device
  2023-06-29  2:53 [PATCH v2] pci: add O_CLOEXEC when open uio device Weifeng Su
@ 2023-07-06 20:04 ` Stephen Hemminger
  0 siblings, 0 replies; 2+ messages in thread
From: Stephen Hemminger @ 2023-07-06 20:04 UTC (permalink / raw)
  To: Weifeng Su; +Cc: dev, stable, linfeilong

On Thu, 29 Jun 2023 10:53:39 +0800
Weifeng Su <suweifeng1@huawei.com> wrote:

> In this scenario, the DPDK process invokes a script which
> inherits an open file descriptor (FD) for a UIO device.
> After the script execution is complete, the UIO device's
> close operation is called. However, in a new kernel version
> (865a11f987ab5f03:uio/uio_pci_generic: Disable bus-mastering on release),
> this close operation causes the PCI bus master bit to be cleared,
> rendering the device unusable and leading to unexpected behavior.
> 
> This modification was made to prevent the UIO device's FD
> from being inherited by the child process.
> 
> Signed-off-by: Weifeng Su <suweifeng1@huawei.com>

Makes sense, the eventfd used form VFIO is already marked as close on exec.

Acked-by: Stephen Hamminger <stephen@networkplumber.org>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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