Hi, even with the below patch applied ? https://patchwork.kernel.org/patch/9452265/ regards shafi ________________________________________ From: Michael Ney <neym@xxxxxxxxxxxx> Sent: 06 February 2017 17:46 To: Mohammed Shafi Shajakhan Cc: Valo, Kalle; linux-wireless@xxxxxxxxxxxxxxx; ath10k@xxxxxxxxxxxxxxxxxxx; Shajakhan, Mohammed Shafi (Mohammed Shafi) Subject: Re: [PATCH v3] ath10k: Fix crash during rmmod when probe firmware fails Symmetry is still broken on firmware crash (at least with 6174). ath10k_pci_hif_stop gets called twice, once from the driver restart (warm restart) and once from ieee80211 start (cold restart), resulting in napi_synchrionize/napi_disable getting called twice and sticking the driver in an infinite wait loop (napi_synchronize waits until NAPI_STATE_SCHED is off, while napi_disable leaves NAPI_STATE_SCHED to on when leaving). > On Feb 6, 2017, at 5:04 AM, Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxx> wrote: > > Hi Kalle, > > the change suggested by you helps, and the device probe, scan > is successful as well. Still good to have this change part of your > basic sanity and regression testing ! > > regards, > shafi > > On Wed, Jan 25, 2017 at 01:46:28PM +0000, Valo, Kalle wrote: >> Kalle Valo <kvalo@xxxxxxxxxxxxxxxx> writes: >> >>> Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> writes: >>> >>>> From: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> >>>> >>>> This fixes the below crash when ath10k probe firmware fails, >>>> NAPI polling tries to access a rx ring resource which was never >>>> allocated, fix this by disabling NAPI right away once the probe >>>> firmware fails by calling 'ath10k_hif_stop'. Its good to note >>>> that the error is never propogated to 'ath10k_pci_probe' when >>>> ath10k_core_register fails, so calling 'ath10k_hif_stop' to cleanup >>>> PCI related things seems to be ok >>>> >>>> BUG: unable to handle kernel NULL pointer dereference at (null) >>>> IP: __ath10k_htt_rx_ring_fill_n+0x19/0x230 [ath10k_core] >>>> __ath10k_htt_rx_ring_fill_n+0x19/0x230 [ath10k_core] >>>> >>>> Call Trace: >>>> >>>> [<ffffffffa113ec62>] ath10k_htt_rx_msdu_buff_replenish+0x42/0x90 >>>> [ath10k_core] >>>> [<ffffffffa113f393>] ath10k_htt_txrx_compl_task+0x433/0x17d0 >>>> [ath10k_core] >>>> [<ffffffff8114406d>] ? __wake_up_common+0x4d/0x80 >>>> [<ffffffff811349ec>] ? cpu_load_update+0xdc/0x150 >>>> [<ffffffffa119301d>] ? ath10k_pci_read32+0xd/0x10 [ath10k_pci] >>>> [<ffffffffa1195b17>] ath10k_pci_napi_poll+0x47/0x110 [ath10k_pci] >>>> [<ffffffff817863af>] net_rx_action+0x20f/0x370 >>>> >>>> Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx> >>>> Fixes: 3c97f5de1f28 ("ath10k: implement NAPI support") >>>> Signed-off-by: Mohammed Shafi Shajakhan <mohammed@xxxxxxxxxxxxxxxx> >>> >>> Is there an easy way to reproduce this bug? I don't see it on my x86 >>> laptop with qca988x and I call rmmod all the time. I would like to test >>> this myself. >>> >>>> --- a/drivers/net/wireless/ath/ath10k/core.c >>>> +++ b/drivers/net/wireless/ath/ath10k/core.c >>>> @@ -2164,6 +2164,7 @@ static int ath10k_core_probe_fw(struct ath10k *ar) >>>> ath10k_core_free_firmware_files(ar); >>>> >>>> err_power_down: >>>> + ath10k_hif_stop(ar); >>>> ath10k_hif_power_down(ar); >>>> >>>> return ret; >>> >>> This breaks the symmetry, we should not be calling ath10k_hif_stop() if >>> we haven't called ath10k_hif_start() from the same function. This can >>> just create a bigger mess later, for example with other bus support like >>> sdio or usb. In theory it should enough that we call >>> ath10k_hif_power_down() and pci.c does the rest correctly "behind the >>> scenes". >>> >>> I investigated this a bit and I think the real cause is that we call >>> napi_enable() from ath10k_pci_hif_power_up() and napi_disable() from >>> ath10k_pci_hif_stop(). Does anyone remember why? >>> >>> I was expecting that we would call napi_enable()/napi_disable() either >>> in ath10k_hif_power_up/down() or ath10k_hif_start()/stop(), but not >>> mixed like it's currently. >> >> So below is something I was thinking of, now napi_enable() is called >> from ath10k_hif_start() and napi_disable() from ath10k_hif_stop(). Would >> that work? >> >> --- a/drivers/net/wireless/ath/ath10k/pci.c >> +++ b/drivers/net/wireless/ath/ath10k/pci.c >> @@ -1648,6 +1648,8 @@ static int ath10k_pci_hif_start(struct ath10k *ar) >> >> ath10k_dbg(ar, ATH10K_DBG_BOOT, "boot hif start\n"); >> >> + napi_enable(&ar->napi); >> + >> ath10k_pci_irq_enable(ar); >> ath10k_pci_rx_post(ar); >> >> @@ -2532,7 +2534,6 @@ static int ath10k_pci_hif_power_up(struct ath10k *ar) >> ath10k_err(ar, "could not wake up target CPU: %d\n", ret); >> goto err_ce; >> } >> - napi_enable(&ar->napi); >> >> return 0; >> >> -- >> Kalle Valo > > _______________________________________________ > ath10k mailing list > ath10k@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/ath10k
