Date: Thu, 11 Dec 2025 00:46:52 +0000 From: Bjoern A. Zeeb <bz@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 567a097c8ab6 - main - LinuxKPI: 802.11: lock down the "txq_scheduled" tailq Message-ID: <693a147c.267f3.1f34bc6e@gitrepo.freebsd.org>
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The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=567a097c8ab60d9fcd68a87c3c5ad605fe8715cc commit 567a097c8ab60d9fcd68a87c3c5ad605fe8715cc Author: Bjoern A. Zeeb <bz@FreeBSD.org> AuthorDate: 2025-12-10 20:29:23 +0000 Commit: Bjoern A. Zeeb <bz@FreeBSD.org> CommitDate: 2025-12-11 00:46:15 +0000 LinuxKPI: 802.11: lock down the "txq_scheduled" tailq For consistency rename the "scheduled_txqs" tailq to "txq_scheduled" and add a lock per txq ("txq_scheduled_lock[]"). We use the "_bh" locking as this called from the device driver. This fixes panics due to concurrent access to the tailq, especially in between "first" and "remove" on the out-direction and between "insert" and "elem_init" on the in-direction. This was easily reproducible just running iperf3 at basic rates for a few seconds to minutes with multiple chipsets, not only rtw89. Sponsored by: The FreeBSD Foundation PR: 290636 Reported by: arved, and others before MFC after: 3 days --- sys/compat/linuxkpi/common/src/linux_80211.c | 51 ++++++++++++++++++++++------ sys/compat/linuxkpi/common/src/linux_80211.h | 3 +- 2 files changed, 42 insertions(+), 12 deletions(-) diff --git a/sys/compat/linuxkpi/common/src/linux_80211.c b/sys/compat/linuxkpi/common/src/linux_80211.c index 8098d02da1a9..1d510577f00c 100644 --- a/sys/compat/linuxkpi/common/src/linux_80211.c +++ b/sys/compat/linuxkpi/common/src/linux_80211.c @@ -6472,8 +6472,9 @@ linuxkpi_ieee80211_alloc_hw(size_t priv_len, const struct ieee80211_ops *ops) TAILQ_INIT(&lhw->lvif_head); __hw_addr_init(&lhw->mc_list); for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) { + spin_lock_init(&lhw->txq_scheduled_lock[ac]); lhw->txq_generation[ac] = 1; - TAILQ_INIT(&lhw->scheduled_txqs[ac]); + TAILQ_INIT(&lhw->txq_scheduled[ac]); } /* Chanctx_conf */ @@ -6507,6 +6508,7 @@ linuxkpi_ieee80211_iffree(struct ieee80211_hw *hw) { struct lkpi_hw *lhw; struct mbuf *m; + int ac; lhw = HW_TO_LHW(hw); free(lhw->ic, M_LKPI80211); @@ -6571,6 +6573,9 @@ linuxkpi_ieee80211_iffree(struct ieee80211_hw *hw) lkpi_cleanup_mcast_list_locked(lhw); LKPI_80211_LHW_MC_UNLOCK(lhw); + for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) + spin_lock_destroy(&lhw->txq_scheduled_lock[ac]); + /* Cleanup more of lhw here or in wiphy_free()? */ spin_lock_destroy(&lhw->txq_lock); LKPI_80211_LHW_TXQ_LOCK_DESTROY(lhw); @@ -8664,7 +8669,12 @@ linuxkpi_ieee80211_wake_queue(struct ieee80211_hw *hw, int qnum) spin_unlock_irqrestore(&lhw->txq_lock, flags); } +/* -------------------------------------------------------------------------- */ + /* This is just hardware queues. */ +/* + * Being called from the driver thus use _bh() locking. + */ void linuxkpi_ieee80211_txq_schedule_start(struct ieee80211_hw *hw, uint8_t ac) { @@ -8672,10 +8682,16 @@ linuxkpi_ieee80211_txq_schedule_start(struct ieee80211_hw *hw, uint8_t ac) lhw = HW_TO_LHW(hw); - IMPROVE_TXQ("Are there reasons why we wouldn't schedule?"); - IMPROVE_TXQ("LOCKING"); + if (ac >= IEEE80211_NUM_ACS) { + ic_printf(lhw->ic, "%s: ac %u out of bounds.\n", __func__, ac); + return; + } + + spin_lock_bh(&lhw->txq_scheduled_lock[ac]); + IMPROVE("check AIRTIME_FAIRNESS"); if (++lhw->txq_generation[ac] == 0) lhw->txq_generation[ac]++; + spin_unlock_bh(&lhw->txq_scheduled_lock[ac]); } struct ieee80211_txq * @@ -8688,24 +8704,33 @@ linuxkpi_ieee80211_next_txq(struct ieee80211_hw *hw, uint8_t ac) lhw = HW_TO_LHW(hw); txq = NULL; - IMPROVE_TXQ("LOCKING"); + if (ac >= IEEE80211_NUM_ACS) { + ic_printf(lhw->ic, "%s: ac %u out of bounds.\n", __func__, ac); + return (NULL); + } + + spin_lock_bh(&lhw->txq_scheduled_lock[ac]); /* Check that we are scheduled. */ if (lhw->txq_generation[ac] == 0) goto out; - ltxq = TAILQ_FIRST(&lhw->scheduled_txqs[ac]); + ltxq = TAILQ_FIRST(&lhw->txq_scheduled[ac]); if (ltxq == NULL) goto out; if (ltxq->txq_generation == lhw->txq_generation[ac]) goto out; + IMPROVE("check AIRTIME_FAIRNESS"); + + TAILQ_REMOVE(&lhw->txq_scheduled[ac], ltxq, txq_entry); ltxq->txq_generation = lhw->txq_generation[ac]; - TAILQ_REMOVE(&lhw->scheduled_txqs[ac], ltxq, txq_entry); txq = <xq->txq; TAILQ_ELEM_INIT(ltxq, txq_entry); out: + spin_unlock_bh(&lhw->txq_scheduled_lock[ac]); + return (txq); } @@ -8718,8 +8743,6 @@ void linuxkpi_ieee80211_schedule_txq(struct ieee80211_hw *hw, ltxq = TXQ_TO_LTXQ(txq); - IMPROVE_TXQ("LOCKING"); - /* Only schedule if work to do or asked to anyway. */ LKPI_80211_LTXQ_LOCK(ltxq); ltxq_empty = skb_queue_empty(<xq->skbq); @@ -8727,20 +8750,26 @@ void linuxkpi_ieee80211_schedule_txq(struct ieee80211_hw *hw, if (!withoutpkts && ltxq_empty) goto out; + lhw = HW_TO_LHW(hw); + spin_lock_bh(&lhw->txq_scheduled_lock[txq->ac]); /* * Make sure we do not double-schedule. We do this by checking tqe_prev, * the previous entry in our tailq. tqe_prev is always valid if this entry * is queued, tqe_next may be NULL if this is the only element in the list. */ if (ltxq->txq_entry.tqe_prev != NULL) - goto out; + goto unlock; + + TAILQ_INSERT_TAIL(&lhw->txq_scheduled[txq->ac], ltxq, txq_entry); +unlock: + spin_unlock_bh(&lhw->txq_scheduled_lock[txq->ac]); - lhw = HW_TO_LHW(hw); - TAILQ_INSERT_TAIL(&lhw->scheduled_txqs[txq->ac], ltxq, txq_entry); out: return; } +/* -------------------------------------------------------------------------- */ + void linuxkpi_ieee80211_handle_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq) diff --git a/sys/compat/linuxkpi/common/src/linux_80211.h b/sys/compat/linuxkpi/common/src/linux_80211.h index 0dfcd7646c34..fcbef46fc6de 100644 --- a/sys/compat/linuxkpi/common/src/linux_80211.h +++ b/sys/compat/linuxkpi/common/src/linux_80211.h @@ -252,7 +252,8 @@ struct lkpi_hw { /* name it mac80211_sc? */ struct mtx txq_mtx; uint32_t txq_generation[IEEE80211_NUM_ACS]; - TAILQ_HEAD(, lkpi_txq) scheduled_txqs[IEEE80211_NUM_ACS]; + spinlock_t txq_scheduled_lock[IEEE80211_NUM_ACS]; + TAILQ_HEAD(, lkpi_txq) txq_scheduled[IEEE80211_NUM_ACS]; spinlock_t txq_lock; /* Deferred RX path. */
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