This is a note to let you know that I've just added the patch titled cxgb4: Properly lock TX queue for the selftest. to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cxgb4-properly-lock-tx-queue-for-the-selftest.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 33414aa81ccdab06512054d5d1e0c0b94bf98a29 Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Date: Mon Apr 29 11:11:47 2024 +0200 cxgb4: Properly lock TX queue for the selftest. [ Upstream commit 9067eccdd7849dd120d5495dbd5a686fa6ed2c1a ] The selftest for the driver sends a dummy packet and checks if the packet will be received properly as it should be. The regular TX path and the selftest can use the same network queue so locking is required and was missing in the selftest path. This was addressed in the commit cited below. Unfortunately locking the TX queue requires BH to be disabled which is not the case in selftest path which is invoked in process context. Lockdep should be complaining about this. Use __netif_tx_lock_bh() for TX queue locking. Fixes: c650e04898072 ("cxgb4: Fix race between loopback and normal Tx path") Reported-by: "John B. Wyatt IV" <jwyatt@xxxxxxxxxx> Closes: https://lore.kernel.org/all/Zic0ot5aGgR-V4Ks@thinkpad2021/ Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240429091147.YWAaal4v@xxxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c index 98dd78551d89a..fff1ce835bc0d 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c @@ -2684,12 +2684,12 @@ int cxgb4_selftest_lb_pkt(struct net_device *netdev) lb->loopback = 1; q = &adap->sge.ethtxq[pi->first_qset]; - __netif_tx_lock(q->txq, smp_processor_id()); + __netif_tx_lock_bh(q->txq); reclaim_completed_tx(adap, &q->q, -1, true); credits = txq_avail(&q->q) - ndesc; if (unlikely(credits < 0)) { - __netif_tx_unlock(q->txq); + __netif_tx_unlock_bh(q->txq); return -ENOMEM; } @@ -2724,7 +2724,7 @@ int cxgb4_selftest_lb_pkt(struct net_device *netdev) init_completion(&lb->completion); txq_advance(&q->q, ndesc); cxgb4_ring_tx_db(adap, &q->q, ndesc); - __netif_tx_unlock(q->txq); + __netif_tx_unlock_bh(q->txq); /* wait for the pkt to return */ ret = wait_for_completion_timeout(&lb->completion, 10 * HZ);