> -----Original Message-----
> From: Deren Wu <deren.wu@xxxxxxxxxxxx>
> Sent: Saturday, January 13, 2024 5:00 PM
> To: Felix Fietkau <nbd@xxxxxxxx>; Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> Cc: Sean Wang <sean.wang@xxxxxxxxxxxx>; Soul Huang <Soul.Huang@xxxxxxxxxxxx>; Ming Yen Hsieh
> <mingyen.hsieh@xxxxxxxxxxxx>; Leon Yen <Leon.Yen@xxxxxxxxxxxx>; Eric-SY Chang
> <Eric-SY.Chang@xxxxxxxxxxxx>; KM Lin <km.lin@xxxxxxxxxxxx>; Robin Chiu <robin.chiu@xxxxxxxxxxxx>; CH Yeh
> <ch.yeh@xxxxxxxxxxxx>; Posh Sun <posh.sun@xxxxxxxxxxxx>; Quan Zhou <quan.zhou@xxxxxxxxxxxx>; Ryder Lee
> <ryder.lee@xxxxxxxxxxxx>; Shayne Chen <shayne.chen@xxxxxxxxxxxx>; linux-wireless
> <linux-wireless@xxxxxxxxxxxxxxx>; linux-mediatek <linux-mediatek@xxxxxxxxxxxxxxxxxxx>; Deren Wu
> <deren.wu@xxxxxxxxxxxx>
> Subject: [PATCH 1/2] wifi: mt76: mt7921e: fix use-after-free in free_irq()
>
> From commit a304e1b82808 ("[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@xxxxxxxxx>
> Closes:
> https://lore.kernel.org/linux-wireless/CABXGCsOdvVwdLmSsC8TZ1jF0UOg_F_W3wqLECWX620PUkvNk=A@mail.gmail.
> com/
> Fixes: 9270270d6219 ("wifi: mt76: mt7921: fix PCI DMA hang after reboot")
> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@xxxxxxxxx>
> Signed-off-by: Deren Wu <deren.wu@xxxxxxxxxxxx>
> ---
> drivers/net/wireless/mediatek/mt76/mt7921/pci.c | 1 +
> drivers/net/wireless/mediatek/mt76/mt792x_dma.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
> b/drivers/net/wireless/mediatek/mt76/mt7921/pci.c
> index 57903c6e4f11..2f04d6658b6b 100644
> --- 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);
Can it do below like mt7921_pci_suspend() to safely stop interrupt handler?
Instead of setting a flag.
synchronize_irq(pdev->irq);
tasklet_kill(&mdev->irq_tasklet);
> 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
> index 488326ce5ed4..3893dbe866fe 100644
> --- 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 PCI is removed, is it still safe to access '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))
> --
> 2.18.0
>
