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Date:      Tue, 04 Aug 2026 17:15:26 +0000
From:      Alexander Leidinger <netchild@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject:   git: 65349af4422f - main - iflib: clear the deferred TX descriptor state when a queue is stopped
Message-ID:  <6a721e2e.2286f.16affed0@gitrepo.freebsd.org>
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The branch main has been updated by netchild:

URL: https://cgit.FreeBSD.org/src/commit/?id=65349af4422ffffe40850168c5feb808d43ad06d

commit 65349af4422ffffe40850168c5feb808d43ad06d
Author:     Alexander Leidinger <netchild@FreeBSD.org>
AuthorDate: 2026-08-04 16:44:54 +0000
Commit:     Alexander Leidinger <netchild@FreeBSD.org>
CommitDate: 2026-08-04 17:14:58 +0000

    iflib: clear the deferred TX descriptor state when a queue is stopped
    
    Stopping an interface frees the queued mbufs and zeroes a transmit
    queue's descriptor accounting, but the three counters that track
    descriptors deferred to a later doorbell write or report-status
    request are not cleared there: they only reach zero when the code
    that acts on them runs.  After a reset they therefore describe
    descriptors that no longer exist, until enough new traffic flushes
    them.
    
    The consequences are small - one doorbell written from a stale
    count, and a report-status request on the first packet after the
    reset - but the state is simply wrong, and the transmit-hang check
    in iflib_timer() reads one of them.
    
    MFC after:      1 week
    Assisted-by:    Claude Code (Opus 5)
---
 sys/net/iflib.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/net/iflib.c b/sys/net/iflib.c
index f865f2414281..63455fb46d70 100644
--- a/sys/net/iflib.c
+++ b/sys/net/iflib.c
@@ -2701,6 +2701,8 @@ iflib_stop(if_ctx_t ctx)
 		txq->ift_outstanding_prev = 0;
 		txq->ift_wdog_armed = 0;
 		txq->ift_in_use = txq->ift_gen = txq->ift_no_desc_avail = 0;
+		txq->ift_npending = txq->ift_db_pending = 0;
+		txq->ift_rs_pending = 0;
 		if (sctx->isc_flags & IFLIB_PRESERVE_TX_INDICES)
 			txq->ift_cidx = txq->ift_pidx;
 		else
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