On 10/19/2018 12:06 AM, Ferruh Yigit wrote:
On 10/18/2018 7:27 AM, Jeff Guo wrote:
When a device is hot-unplugged, pci_remove will be invoked unexpectedly
before pci_release, it will caused kernel hung issue which will throw the
error info of "Trying to free already-free IRQ XXX". And on the other hand,
if pci_remove before pci_release, the interrupt will not got chance to be
disabled. So this patch aim to fix this issue by adding pci_release call
in pci_remove, it will gurranty that all pci clean up will be done before
pci removal.
Signed-off-by: Jeff Guo <jia....@intel.com>
---
kernel/linux/igb_uio/igb_uio.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c
index fede66c..3cf394b 100644
--- a/kernel/linux/igb_uio/igb_uio.c
+++ b/kernel/linux/igb_uio/igb_uio.c
@@ -570,6 +570,8 @@ igbuio_pci_remove(struct pci_dev *dev)
{
struct rte_uio_pci_dev *udev = pci_get_drvdata(dev);
+ igbuio_pci_release(&udev->info, NULL);
+
Hi Jeff,
This is simpler approach comparing to previous version.
And do you know if igbuio_pci_release() won't be called after
igbuio_pci_remove() because that will also cause crash, and indeed it will cause
a crash in the uio too.
The flow as far as I can see:
when uioN device opened by application, igbuio_pci_open() is called.
If device removed, I expect driver remove() function called, which has a call
stack like below:
igbuio_pci_remove()
uio_unregister_device()
uio_device_release()
kfree(struct uio_device)
After this point udev is freed and igbuio_pci_release() shouldn't be called, so
I assume uioN device closed before this point but I couldn't find where, if not
closed, closing it later will crash.
What i saw is that after igb_uio remove , if detach the device the pci
release will be called, so the
igbuo_pci_release should be called again.
I can't test the hotplug case, can you please confirm above patch fixing crashes
you observed for your use cases?
yes, it could be fix the crashed i observed right now.
And for regular usecase this change shouldn't cause any problem, so at worst it
may not be fixing all hotplug issues, which looks safe to get.
I think it would fix this hung issue that caused of double free irq and
would not have side effect anyway.
