Re: [RESEND PATCH ath-current 2/3] wifi: ath11k: fix NULL dereference in ahb remove when QMI init incomplete

[Miaoqing Pan <miaoqing.pan@oss.qualcomm.com>]

On 7/31/2026 5:24 PM, Rameshkumar Sundaram wrote:
> On 7/30/2026 8:39 AM, Miaoqing Pan wrote:
>> On WCN6750, if QMI messages never arrive (for example when qrtr_smd
>> is not ready), WLAN initialization stops before the device is fully
>> registered. In this case ATH11K_FLAG_QMI_FAIL is not set because no
>> QMI event handler is executed.
>>
>> When the driver is removed, ath11k_ahb_remove() still calls
>> ath11k_core_deinit(), which eventually triggers
>> ath11k_ce_cleanup_pipes() on uninitialized CE pipes and results in a
>> NULL pointer dereference in ath11k_hal_srng_access_begin():
>>
>>    ath11k_hal_srng_access_begin+0x14/0x68 [ath11k]
>>    ath11k_ce_cleanup_pipes+0x184/0x190 [ath11k]
>>    ath11k_pcic_stop+0x24/0x38 [ath11k]
>>    ath11k_core_deinit+0xfc/0x1c0 [ath11k]
>>    ath11k_ahb_remove+0x38/0xa0 [ath11k_ahb]
>>
>> Fix this by invoking ath11k_ahb_remove_prepare() before the state
>> check and skipping ath11k_core_deinit() when either QMI initialization
>> failed or the device was never registered. If ATH11K_FLAG_REGISTERED
>> is not set, core initialization did not complete and CE pipes may
>> remain uninitialized, making ath11k_core_deinit() unsafe.
>>
>> Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.2.0.c2-00204-QCAMSLSWPLZ-1
>>
>> Fixes: 00402f49d26f ("ath11k: Add support for WCN6750 device")
>> Signed-off-by: Miaoqing Pan <miaoqing.pan@oss.qualcomm.com>
>> ---
>>   drivers/net/wireless/ath/ath11k/ahb.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath11k/ahb.c b/drivers/net/ 
>> wireless/ath/ath11k/ahb.c
>> index fb5640882b98..7f5f5c8d7c56 100644
>> --- a/drivers/net/wireless/ath/ath11k/ahb.c
>> +++ b/drivers/net/wireless/ath/ath11k/ahb.c
>> @@ -1265,14 +1265,16 @@ static void ath11k_ahb_remove(struct 
>> platform_device *pdev)
>>   {
>>       struct ath11k_base *ab = platform_get_drvdata(pdev);
>> -    if (test_bit(ATH11K_FLAG_QMI_FAIL, &ab->dev_flags)) {
>> +    ath11k_ahb_remove_prepare(ab);
>> +
>> +    if (test_bit(ATH11K_FLAG_QMI_FAIL, &ab->dev_flags) ||
>> +        !test_bit(ATH11K_FLAG_REGISTERED, &ab->dev_flags)) {
> 
> Can we use ATH11K_FLAG_REGISTERED alone to decide the cleanup path? If 
> REGISTERED is set, ath11k_core_qmi_firmware_ready() completed at least 
> once and the normal ath11k_core_deinit() path should run. If QMI failed 
> on recovery (say before FW_READY or INIT_DONE) this should still do 
> core_deinit() isn't ?
> 
> 
During SSR recovery, it is possible for a QMI failure to occur after the 
device has already been registered, which could result in both 
ATH11K_FLAG_REGISTERED and ATH11K_FLAG_QMI_FAIL being set at the same time.
>>           ath11k_ahb_power_down(ab, false);
>>           ath11k_debugfs_soc_destroy(ab);
>>           ath11k_qmi_deinit_service(ab);
>>           goto qmi_fail;
>>       }
>> -    ath11k_ahb_remove_prepare(ab);
>>       ath11k_core_deinit(ab);
>>   qmi_fail:
> 
> 
> 
> -- 
> Ramesh