wifi: mt76: mt7921e: fix use-after-free in free_irq()

deren · nbd168 · commit c957280ef6ab · 2024-02-22T09:55:19.000+01:00
From commit a304e1b ("[PATCH] Debug shared irqs"), there is a test to make sure the shared irq handler should be able to handle the unexpected event after deregistration. For this case, let's apply MT76_REMOVED flag to indicate the device was removed and do not run into the resource access anymore. BUG: KASAN: use-after-free in mt7921_irq_handler+0xd8/0x100 [mt7921e] Read of size 8 at addr ffff88824a7d3b78 by task rmmod/11115 CPU: 28 PID: 11115 Comm: rmmod Tainted: G W L 5.17.0 #10 Hardware name: Micro-Star International Co., Ltd. MS-7D73/MPG B650I EDGE WIFI (MS-7D73), BIOS 1.81 01/05/2024 Call Trace: <TASK> dump_stack_lvl+0x6f/0xa0 print_address_description.constprop.0+0x1f/0x190 ? mt7921_irq_handler+0xd8/0x100 [mt7921e] ? mt7921_irq_handler+0xd8/0x100 [mt7921e] kasan_report.cold+0x7f/0x11b ? mt7921_irq_handler+0xd8/0x100 [mt7921e] mt7921_irq_handler+0xd8/0x100 [mt7921e] free_irq+0x627/0xaa0 devm_free_irq+0x94/0xd0 ? devm_request_any_context_irq+0x160/0x160 ? kobject_put+0x18d/0x4a0 mt7921_pci_remove+0x153/0x190 [mt7921e] pci_device_remove+0xa2/0x1d0 __device_release_driver+0x346/0x6e0 driver_detach+0x1ef/0x2c0 bus_remove_driver+0xe7/0x2d0 ? __check_object_size+0x57/0x310 pci_unregister_driver+0x26/0x250 __do_sys_delete_module+0x307/0x510 ? free_module+0x6a0/0x6a0 ? fpregs_assert_state_consistent+0x4b/0xb0 ? rcu_read_lock_sched_held+0x10/0x70 ? syscall_enter_from_user_mode+0x20/0x70 ? trace_hardirqs_on+0x1c/0x130 do_syscall_64+0x5c/0x80 ? trace_hardirqs_on_prepare+0x72/0x160 ? do_syscall_64+0x68/0x80 ? trace_hardirqs_on_prepare+0x72/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Closes: https://lore.kernel.org/linux-wireless/CABXGCsOdvVwdLmSsC8TZ1jF0UOg_F_W3wqLECWX620PUkvNk=A@mail.gmail.com/ Fixes: 9270270 ("wifi: mt76: mt7921: fix PCI DMA hang after reboot") Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Signed-off-by: Deren Wu <deren.wu@mediatek.com> Signed-off-by: Felix Fietkau <nbd@nbd.name>
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
@@ -387,6 +387,7 @@ static void mt7921_pci_remove(struct pci_dev *pdev)
 	struct mt792x_dev *dev = container_of(mdev, struct mt792x_dev, mt76);
 
 	mt7921e_unregister_device(dev);
+	set_bit(MT76_REMOVED, &mdev->phy.state);
 	devm_free_irq(&pdev->dev, pdev->irq, dev);
 	mt76_free_device(&dev->mt76);
 	pci_free_irq_vectors(pdev);
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_dma.c b/drivers/net/wireless/mediatek/mt76/mt792x_dma.c
@@ -12,6 +12,8 @@ irqreturn_t mt792x_irq_handler(int irq, void *dev_instance)
 {
 	struct mt792x_dev *dev = dev_instance;
 
+	if (test_bit(MT76_REMOVED, &dev->mt76.phy.state))
+		return IRQ_NONE;
 	mt76_wr(dev, dev->irq_map->host_irq_enable, 0);
 
 	if (!test_bit(MT76_STATE_INITIALIZED, &dev->mphy.state))

Original file line number	Diff line number	Diff line change
`@@ -12,6 +12,8 @@ irqreturn_t mt792x_irq_handler(int irq, void *dev_instance)`
`12`	`12`	`{`
`13`	`13`	`struct mt792x_dev *dev = dev_instance;`
`14`	`14`
	`15`	`+ if (test_bit(MT76_REMOVED, &dev->mt76.phy.state))`
	`16`	`+ return IRQ_NONE;`
`15`	`17`	`mt76_wr(dev, dev->irq_map->host_irq_enable, 0);`
`16`	`18`
`17`	`19`	`if (!test_bit(MT76_STATE_INITIALIZED, &dev->mphy.state))`