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wifi: mt76: mt7925: Fix unregister deadlock

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During device shutdown or removal, a deadlock can occur between the
PCIe remove path and the driver's asynchronous reset work.

The unregistration path calls napi_disable() before cancelling the
reset work. If the reset work runs concurrently, it may re-enable NAPI
and schedule it. Because the device is being unregistered, this can
lead to NAPI state corruption where NAPI is marked as scheduled but
never polled, causing subsequent napi_disable() calls to hang forever.

Fix this by:
1. Moving cancel_work_sync(&dev->reset_work) to the very start of
   mt7925e_unregister_device(), ensuring it is stopped before NAPI
   is disabled.
2. Setting the MT76_REMOVED flag early in the PCI remove path to
   prevent new reset work from being queued.
3. Checking MT76_REMOVED in mt7925_mac_reset_work() and aborting the
   reset early if the device is being removed.

Co-developed-by: Fei Shao <[email protected]>
Signed-off-by: JB Tsai <[email protected]>
Tested-by: Rafael Passos <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>
This commit is contained in:
JB Tsai
2026-07-21 15:34:22 +02:00
committed by Felix Fietkau
parent f8757dd2bf
commit 98c13eb564
2 changed files with 9 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
mt7925/mac.c
+7
View File
@@ -1525,6 +1525,9 @@ void mt7925_mac_reset_work(struct work_struct *work)
cancel_work_sync(&pm->wake_work); cancel_work_sync(&pm->wake_work);
for (i = 0; i < 10; i++) { for (i = 0; i < 10; i++) {
if (test_bit(MT76_REMOVED, &dev->mphy.state))
goto out;
mutex_lock(&dev->mt76.mutex); mutex_lock(&dev->mt76.mutex);
ret = mt792x_dev_reset(dev); ret = mt792x_dev_reset(dev);
mutex_unlock(&dev->mt76.mutex); mutex_unlock(&dev->mt76.mutex);
@@ -1547,8 +1550,12 @@ void mt7925_mac_reset_work(struct work_struct *work)
ieee80211_scan_completed(dev->mphy.hw, &info); ieee80211_scan_completed(dev->mphy.hw, &info);
} }
out:
dev->hw_full_reset = false; dev->hw_full_reset = false;
pm->suspended = false; pm->suspended = false;
if (test_bit(MT76_REMOVED, &dev->mphy.state))
return;
ieee80211_wake_queues(hw); ieee80211_wake_queues(hw);
ieee80211_iterate_active_interfaces(hw, ieee80211_iterate_active_interfaces(hw,
IEEE80211_IFACE_ITER_RESUME_ALL, IEEE80211_IFACE_ITER_RESUME_ALL,
mt7925/pci.c
+2 -2
View File
@@ -47,13 +47,13 @@ static void mt7925e_unregister_device(struct mt792x_dev *dev)
if (dev->phy.chip_cap & MT792x_CHIP_CAP_WF_RF_PIN_CTRL_EVT_EN) if (dev->phy.chip_cap & MT792x_CHIP_CAP_WF_RF_PIN_CTRL_EVT_EN)
wiphy_rfkill_stop_polling(hw->wiphy); wiphy_rfkill_stop_polling(hw->wiphy);
cancel_work_sync(&dev->reset_work);
cancel_work_sync(&dev->init_work); cancel_work_sync(&dev->init_work);
mt76_unregister_device(&dev->mt76); mt76_unregister_device(&dev->mt76);
mt76_for_each_q_rx(&dev->mt76, i) mt76_for_each_q_rx(&dev->mt76, i)
napi_disable(&dev->mt76.napi[i]); napi_disable(&dev->mt76.napi[i]);
cancel_delayed_work_sync(&pm->ps_work); cancel_delayed_work_sync(&pm->ps_work);
cancel_work_sync(&pm->wake_work); cancel_work_sync(&pm->wake_work);
cancel_work_sync(&dev->reset_work);
mt7925_tx_token_put(dev); mt7925_tx_token_put(dev);
__mt792x_mcu_drv_pmctrl(dev); __mt792x_mcu_drv_pmctrl(dev);
@@ -721,8 +721,8 @@ static void mt7925_pci_remove(struct pci_dev *pdev)
struct mt76_dev *mdev = pci_get_drvdata(pdev); struct mt76_dev *mdev = pci_get_drvdata(pdev);
struct mt792x_dev *dev = container_of(mdev, struct mt792x_dev, mt76); struct mt792x_dev *dev = container_of(mdev, struct mt792x_dev, mt76);
mt7925e_unregister_device(dev);
set_bit(MT76_REMOVED, &mdev->phy.state); set_bit(MT76_REMOVED, &mdev->phy.state);
mt7925e_unregister_device(dev);
devm_free_irq(&pdev->dev, pdev->irq, dev); devm_free_irq(&pdev->dev, pdev->irq, dev);
mt76_free_device(&dev->mt76); mt76_free_device(&dev->mt76);
pci_free_irq_vectors(pdev); pci_free_irq_vectors(pdev);