Re: [net,v2,1/2] net: liquidio: Fix off-by-one error in setup_nic_devices() cleanup

On Mon, Jan 26, 2026 at 03:56:07PM +0000, Simon Horman wrote:

On Mon, Jan 26, 2026 at 03:50:39PM +0000, Simon Horman wrote:

quoted

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---
net: liquidio: Fix off-by-one error in setup_nic_devices() cleanup

This patch changes the cleanup loop from while(i--) to do{}while(i--)
to ensure that when a device fails to initialize, it gets cleaned up
along with all previously initialized devices.

quoted

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 0732440eeacd..3ba2806f5d1e 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c

@@ -3765,11 +3765,11 @@ static int setup_nic_devices(struct octeon_device *octeon_dev)

 setup_nic_dev_free:

-	while (i--) {
+	do {
 		dev_err(&octeon_dev->pci_dev->dev,
 			"NIC ifidx:%d Setup failed\n", i);
 		liquidio_destroy_nic_device(octeon_dev, i);
-	}
+	} while (i--);

In lio_main.c, setup_nic_devices() can also reach setup_nic_dev_free from
the devlink_alloc() failure path after the main for loop completes. At that
point i equals ifcount (the loop counter has been incremented past the last
valid device).

With the do-while change, the first iteration will call
liquidio_destroy_nic_device(octeon_dev, ifcount) for a device index that
was never initialized. The function has a guard for NULL netdev so it will
not crash, but it will print a spurious error message about a device that
never existed.

The fix works correctly for failures within the loop (which is the case
described in the commit message), but is there a way to handle the
post-loop devlink_alloc() failure case without printing the spurious
error message?

Sorry for not realising this when I made this suggestion in
my review of v1.

Also, I would suggest splitting this patch in two: one patch
per driver.

Hi Simon,

Apologies from my side as well; I overlooked the devlink_alloc failure 
path myself.

As noted, the loop index i is indeed invalid at that point. I will fix
this by decrementing i in the error path to ensure it points to the last
successfully initialized device before cleanup.

I will also split this patch into two separate patches in v3 as requested.

Regards,
Zilin