During ath12k module removal, in ath12k_core_deinit(),
ath12k_mac_destroy() un-registers ah->hw from mac80211 and frees
the ah->hw as well as all the ar's in it. After this
ath12k_core_soc_destroy()-> ath12k_dp_free()-> ath12k_dp_cc_cleanup()
tries to access one of the freed ar's from pending skb.
This is because during mac destroy, driver failed to flush few
data packets, which were accessed later in ath12k_dp_cc_cleanup()
and freed, but using ar from the packet led to this use-after-free.
BUG: KASAN: use-after-free in ath12k_dp_cc_cleanup.part.0+0x5e2/0xd40 [ath12k]
Write of size 4 at addr ffff888150bd3514 by task modprobe/8926
CPU: 0 UID: 0 PID: 8926 Comm: modprobe Not tainted
6.11.0-rc2-wt-ath+ #1746
Hardware name: Intel(R) Client Systems NUC8i7HVK/NUC8i7HVB, BIOS
HNKBLi70.86A.0067.2021.0528.1339 05/28/2021
Call Trace:
<TASK>
dump_stack_lvl+0x7d/0xe0
print_address_description.constprop.0+0x33/0x3a0
print_report+0xb5/0x260
? kasan_addr_to_slab+0x24/0x80
kasan_report+0xd8/0x110
? ath12k_dp_cc_cleanup.part.0+0x5e2/0xd40 [ath12k]
? ath12k_dp_cc_cleanup.part.0+0x5e2/0xd40 [ath12k]
kasan_check_range+0xf3/0x1a0
__kasan_check_write+0x14/0x20
ath12k_dp_cc_cleanup.part.0+0x5e2/0xd40 [ath12k]
ath12k_dp_free+0x178/0x420 [ath12k]
ath12k_core_stop+0x176/0x200 [ath12k]
ath12k_core_deinit+0x13f/0x210 [ath12k]
ath12k_pci_remove+0xad/0x1c0 [ath12k]
pci_device_remove+0x9b/0x1b0
device_remove+0xbf/0x150
device_release_driver_internal+0x3c3/0x580
? __kasan_check_read+0x11/0x20
driver_detach+0xc4/0x190
bus_remove_driver+0x130/0x2a0
driver_unregister+0x68/0x90
pci_unregister_driver+0x24/0x240
? find_module_all+0x13e/0x1e0
ath12k_pci_exit+0x10/0x20 [ath12k]
__do_sys_delete_module+0x32c/0x580
? module_flags+0x2f0/0x2f0
? kmem_cache_free+0xf0/0x410
? __fput+0x56f/0xab0
? __fput+0x56f/0xab0
? debug_smp_processor_id+0x17/0x20
__x64_sys_delete_module+0x4f/0x70
x64_sys_call+0x522/0x9f0
do_syscall_64+0x64/0x130
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f8182c6ac8b
Commit 24de1b7b231c ("wifi: ath12k: fix flush failure in recovery
scenarios") added the change to decrement the pending packets count
in case of recovery which make sense as ah->hw as well all
ar's in it are intact during recovery, but during core deinit there
is no use in decrementing packets count or waking up the empty waitq
as the module is going to be removed also ar's from pending skb's
can't be used and the packets should just be released back.
To fix this, avoid accessing ar from skb->cb when driver is being
unregistered.
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.1.1-00214-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
Fixes: 24de1b7b231c ("wifi: ath12k: fix flush failure in recovery scenarios")
Signed-off-by: Rameshkumar Sundaram <quic_ramess@xxxxxxxxxxx>
---
v2:
- Skipped skb accounting with UNREGISTERING flag instead of vif check.
---
drivers/net/wireless/ath/ath12k/dp.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wireless/ath/ath12k/dp.c b/drivers/net/wireless/ath/ath12k/dp.c
index ecd3b5c76d26..2ab2a7d45be9 100644
--- a/drivers/net/wireless/ath/ath12k/dp.c
+++ b/drivers/net/wireless/ath/ath12k/dp.c
@@ -1202,10 +1202,16 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
if (!skb)
continue;
- skb_cb = ATH12K_SKB_CB(skb);
- ar = skb_cb->ar;
- if (atomic_dec_and_test(&ar->dp.num_tx_pending))
- wake_up(&ar->dp.tx_empty_waitq);
+ /* if we are unregistering, hw would've been destroyed and
+ * ar is no longer valid.
+ */
+ if (!(test_bit(ATH12K_FLAG_UNREGISTERING, &ab->dev_flags))) {
+ skb_cb = ATH12K_SKB_CB(skb);
+ ar = skb_cb->ar;
+
+ if (atomic_dec_and_test(&ar->dp.num_tx_pending))
+ wake_up(&ar->dp.tx_empty_waitq);
+ }
dma_unmap_single(ab->dev, ATH12K_SKB_CB(skb)->paddr,
skb->len, DMA_TO_DEVICE);
base-commit: 8ed36fe71fd60c851540839b105fd1fddc870c61
--
2.34.1
