| Message ID | 1532931051-20118-1-git-send-email-tamizhr@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ath10k: fix kernel panic by moving pci flush after napi_disable | expand |
On 07/29/2018 11:10 PM, Tamizh chelvam wrote: > When continuously running wifi up/down sequence, the napi poll > can be scheduled after the CE buffers being freed by ath10k_pci_flush > > Steps: > In a certain condition, during wifi down below scenario might occur. > > ath10k_stop->ath10k_hif_stop->napi_schedule->ath10k_pci_flush->napi_poll(napi_synchronize). > > In the above scenario, CE buffer entries will be freed up and become NULL in > ath10k_pci_flush. And the napi_poll has been invoked after the flush process > and it will try to get the skb from the CE buffer entry and perform some action on that. > Since the CE buffer already cleaned by pci flush this action will create NULL > pointer dereference and trigger below kernel panic. > > Unable to handle kernel NULL pointer dereference at virtual address 0000005c > PC is at ath10k_pci_htt_rx_cb+0x64/0x3ec [ath10k_pci] > ath10k_pci_htt_rx_cb [ath10k_pci] > ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci] > ath10k_ce_per_engine_service [ath10k_pci] > ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci] > ath10k_ce_per_engine_service_any [ath10k_pci] > ath10k_pci_napi_poll+0x48/0xec [ath10k_pci] > ath10k_pci_napi_poll [ath10k_pci] > net_rx_action+0xac/0x160 > net_rx_action > __do_softirq+0xdc/0x208 > __do_softirq > irq_exit+0x84/0xe0 > irq_exit > __handle_domain_irq+0x80/0xa0 > __handle_domain_irq > gic_handle_irq+0x38/0x5c > gic_handle_irq > __irq_usr+0x44/0x60 > > Tested on QCA4019 and firmware version 10.4.3.2.1.1-00010 I have been testing this for two days while bisecting buggy 10.4 9984 firmware. I still see crashes, but it is certainly no worse. So, this patch seems OK to me. Thanks, Ben
Tamizh chelvam <tamizhr@codeaurora.org> wrote: > When continuously running wifi up/down sequence, the napi poll > can be scheduled after the CE buffers being freed by ath10k_pci_flush > > Steps: > In a certain condition, during wifi down below scenario might occur. > > ath10k_stop->ath10k_hif_stop->napi_schedule->ath10k_pci_flush->napi_poll(napi_synchronize). > > In the above scenario, CE buffer entries will be freed up and become NULL in > ath10k_pci_flush. And the napi_poll has been invoked after the flush process > and it will try to get the skb from the CE buffer entry and perform some action on that. > Since the CE buffer already cleaned by pci flush this action will create NULL > pointer dereference and trigger below kernel panic. > > Unable to handle kernel NULL pointer dereference at virtual address 0000005c > PC is at ath10k_pci_htt_rx_cb+0x64/0x3ec [ath10k_pci] > ath10k_pci_htt_rx_cb [ath10k_pci] > ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci] > ath10k_ce_per_engine_service [ath10k_pci] > ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci] > ath10k_ce_per_engine_service_any [ath10k_pci] > ath10k_pci_napi_poll+0x48/0xec [ath10k_pci] > ath10k_pci_napi_poll [ath10k_pci] > net_rx_action+0xac/0x160 > net_rx_action > __do_softirq+0xdc/0x208 > __do_softirq > irq_exit+0x84/0xe0 > irq_exit > __handle_domain_irq+0x80/0xa0 > __handle_domain_irq > gic_handle_irq+0x38/0x5c > gic_handle_irq > __irq_usr+0x44/0x60 > > Tested on QCA4019 and firmware version 10.4.3.2.1.1-00010 > > Signed-off-by: Tamizh chelvam <tamizhr@codeaurora.org> > Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Patch applied to ath-next branch of ath.git, thanks. bd1d395070cc ath10k: fix kernel panic by moving pci flush after napi_disable
diff --git a/drivers/net/wireless/ath/ath10k/ahb.c b/drivers/net/wireless/ath/ath10k/ahb.c index fa39fff..e244dc5 100644 --- a/drivers/net/wireless/ath/ath10k/ahb.c +++ b/drivers/net/wireless/ath/ath10k/ahb.c @@ -660,10 +660,10 @@ static void ath10k_ahb_hif_stop(struct ath10k *ar) ath10k_ahb_irq_disable(ar); synchronize_irq(ar_ahb->irq); - ath10k_pci_flush(ar); - napi_synchronize(&ar->napi); napi_disable(&ar->napi); + + ath10k_pci_flush(ar); } static int ath10k_ahb_hif_power_up(struct ath10k *ar) diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c index af2cf55..97fa5c7 100644 --- a/drivers/net/wireless/ath/ath10k/pci.c +++ b/drivers/net/wireless/ath/ath10k/pci.c @@ -2068,9 +2068,9 @@ static void ath10k_pci_hif_stop(struct ath10k *ar) ath10k_pci_irq_disable(ar); ath10k_pci_irq_sync(ar); - ath10k_pci_flush(ar); napi_synchronize(&ar->napi); napi_disable(&ar->napi); + ath10k_pci_flush(ar); spin_lock_irqsave(&ar_pci->ps_lock, flags); WARN_ON(ar_pci->ps_wake_refcount > 0);
When continuously running wifi up/down sequence, the napi poll can be scheduled after the CE buffers being freed by ath10k_pci_flush Steps: In a certain condition, during wifi down below scenario might occur. ath10k_stop->ath10k_hif_stop->napi_schedule->ath10k_pci_flush->napi_poll(napi_synchronize). In the above scenario, CE buffer entries will be freed up and become NULL in ath10k_pci_flush. And the napi_poll has been invoked after the flush process and it will try to get the skb from the CE buffer entry and perform some action on that. Since the CE buffer already cleaned by pci flush this action will create NULL pointer dereference and trigger below kernel panic. Unable to handle kernel NULL pointer dereference at virtual address 0000005c PC is at ath10k_pci_htt_rx_cb+0x64/0x3ec [ath10k_pci] ath10k_pci_htt_rx_cb [ath10k_pci] ath10k_ce_per_engine_service+0x74/0xc4 [ath10k_pci] ath10k_ce_per_engine_service [ath10k_pci] ath10k_ce_per_engine_service_any+0x74/0x80 [ath10k_pci] ath10k_ce_per_engine_service_any [ath10k_pci] ath10k_pci_napi_poll+0x48/0xec [ath10k_pci] ath10k_pci_napi_poll [ath10k_pci] net_rx_action+0xac/0x160 net_rx_action __do_softirq+0xdc/0x208 __do_softirq irq_exit+0x84/0xe0 irq_exit __handle_domain_irq+0x80/0xa0 __handle_domain_irq gic_handle_irq+0x38/0x5c gic_handle_irq __irq_usr+0x44/0x60 Tested on QCA4019 and firmware version 10.4.3.2.1.1-00010 Signed-off-by: Tamizh chelvam <tamizhr@codeaurora.org> --- drivers/net/wireless/ath/ath10k/ahb.c | 4 ++-- drivers/net/wireless/ath/ath10k/pci.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)