git: ba353c8950d5 - main - iflib: Drain configuration tasks before interface detach

The branch main has been updated by kbowling:

URL: https://cgit.FreeBSD.org/src/commit/?id=ba353c8950d575f9d15b82c92658e660935fba25

commit ba353c8950d575f9d15b82c92658e660935fba25
Author:     Nick Price <nprice@FreeBSD.org>
AuthorDate: 2026-08-08 06:17:16 +0000
Commit:     Kevin Bowling <kbowling@FreeBSD.org>
CommitDate: 2026-08-14 22:08:36 +0000

    iflib: Drain configuration tasks before interface detach
    
    iflib_device_deregister() sets IFC_IN_DETACH before removing the
    interface, but a task which already passed its detach check can still
    report a link change.  This can re-arm if_linktask after
    ether_ifdetach() has drained it and leave work pending across queue
    teardown.
    
    Drain the entire private taskqueue before ether_ifdetach().  Drivers
    may register their own link-related configuration tasks there, so
    draining only the framework admin task leaves the same race for those
    drivers.
    
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D58452
    
    Co-authored-by: Andrew Gallatin <gallatin@FreeBSD.org>
    Co-authored-by: Kevin Bowling <kbowling@FreeBSD.org>
---
 sys/net/iflib.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/net/iflib.c b/sys/net/iflib.c
index 461ff0ba273e..cda60f174a31 100644
--- a/sys/net/iflib.c
+++ b/sys/net/iflib.c
@@ -5658,6 +5658,13 @@ iflib_device_deregister(if_ctx_t ctx)
 	iflib_unregister_vlan_handlers(ctx);
 
 	iflib_netmap_detach(ifp);
+	/*
+	 * A task that passed its IFC_IN_DETACH check before the flag was set
+	 * can still report a link change.  Drain every private task before
+	 * ether_ifdetach() performs the final if_linktask drain.  Drivers may
+	 * register their own link-related tasks on this taskqueue.
+	 */
+	taskqueue_drain_all(ctx->ifc_tq);
 	ether_ifdetach(ifp);
 
 	CTX_LOCK(ctx);