* [PATCH net-next] tap: report IFF_DETACH_QUEUE in TUNGETIFF
@ 2026-09-29 14:22 Umang Pokhriyal
2026-09-30 15:02 ` Willem de Bruijn
0 siblings, 1 reply; 2+ messages in thread
From: Umang Pokhriyal @ 2026-09-29 14:22 UTC (permalink / raw)
To: Willem de Bruijn, Jason Wang, Andrew Lunn, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: netdev, linux-kernel
tun sets IFF_DETACH_QUEUE in the flags returned by TUNGETIFF when the
queue is detached, since commit 3d407a80b62f ("tun: Report whether the
queue is attached or not"). tap_ioctl() returns only q->flags, so a
detached macvtap or ipvtap queue is reported as attached.
Cloud Hypervisor ran into this when checking queue state on macvtap.
Report the flag from q->enabled, as tun does.
Assisted-by: LLM
Signed-off-by: Umang Pokhriyal <umangpokhriyall@gmail.com>
---
drivers/net/tap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index ff67d99deb39e..cb8ffb0c4a315 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -950,6 +950,8 @@ static long tap_ioctl(struct file *file, unsigned int cmd,
ret = 0;
u = q->flags;
+ if (!q->enabled)
+ u |= IFF_DETACH_QUEUE;
if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) ||
put_user(u, &ifr->ifr_flags))
ret = -EFAULT;
base-commit: c66d93e68728cfb5f40b40d0f24129d7768faf43
--
2.53.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] tap: report IFF_DETACH_QUEUE in TUNGETIFF
2026-09-29 14:22 [PATCH net-next] tap: report IFF_DETACH_QUEUE in TUNGETIFF Umang Pokhriyal
@ 2026-09-30 15:02 ` Willem de Bruijn
0 siblings, 0 replies; 2+ messages in thread
From: Willem de Bruijn @ 2026-09-30 15:02 UTC (permalink / raw)
To: Umang Pokhriyal, Willem de Bruijn, Jason Wang, Andrew Lunn,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni
Cc: netdev, linux-kernel
Umang Pokhriyal wrote:
> tun sets IFF_DETACH_QUEUE in the flags returned by TUNGETIFF when the
> queue is detached, since commit 3d407a80b62f ("tun: Report whether the
> queue is attached or not"). tap_ioctl() returns only q->flags, so a
> detached macvtap or ipvtap queue is reported as attached.
>
> Cloud Hypervisor ran into this when checking queue state on macvtap.
>
> Report the flag from q->enabled, as tun does.
>
> Assisted-by: LLM
> Signed-off-by: Umang Pokhriyal <umangpokhriyall@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
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