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

[Rameshkumar Sundaram]

On 8/3/2026 12:17 PM, Miaoqing Pan wrote:
> 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@xxxxxxxxxxxxxxxx>
> > > ---
> > >   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.

Yeah so in that case current code will skip core_deinit() which should 
actually run isn't ? Though the QMI has failed on recovery the core was 
already initialized and should be torn down.

> > >           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