[PATCH] wifi:ath11k: fix monitor mode bringup crash

[Nagarajan Maran]

When the interface is brought up in monitor mode, it leads
to NULL pointer dereference crash. This crash happens when
the packet type is extracted for a SKB. This extraction
which is present in the received msdu delivery path,is
not needed for the monitor ring packets since they are
all RAW packets. Hence appending the flags with
"RX_FLAG_ONLY_MONITOR" to skip that extraction.

Observed calltrace:

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000064
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000000048517000
[0000000000000064] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in: ath11k_pci ath11k qmi_helpers
CPU: 2 PID: 1781 Comm: napi/-271 Not tainted
6.1.0-rc5-wt-ath-656295-gef907406320c-dirty #6
Hardware name: Qualcomm Technologies, Inc. IPQ8074/AP-HK10-C2 (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ath11k_hw_qcn9074_rx_desc_get_decap_type+0x34/0x60 [ath11k]
lr : ath11k_hw_qcn9074_rx_desc_get_decap_type+0x5c/0x60 [ath11k]
sp : ffff80000ef5bb10
x29: ffff80000ef5bb10 x28: 0000000000000000 x27: ffff000007baafa0
x26: ffff000014a91ed0 x25: 0000000000000000 x24: 0000000000000000
x23: ffff800002b77378 x22: ffff000014a91ec0 x21: ffff000006c8d600
x20: 0000000000000000 x19: ffff800002b77740 x18: 0000000000000006
x17: 736564203634343a x16: 656e694c20657079 x15: 0000000000000143
x14: 00000000ffffffea x13: ffff80000ef5b8b8 x12: ffff80000ef5b8c8
x11: ffff80000a591d30 x10: ffff80000a579d40 x9 : c0000000ffffefff
x8 : 0000000000000003 x7 : 0000000000017fe8 x6 : ffff80000a579ce8
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 3a35ec12ed7f8900 x1 : 0000000000000000 x0 : 0000000000000052
Call trace:
 ath11k_hw_qcn9074_rx_desc_get_decap_type+0x34/0x60 [ath11k]
 ath11k_dp_rx_deliver_msdu.isra.42+0xa4/0x3d0 [ath11k]
 ath11k_dp_rx_mon_deliver.isra.43+0x2f8/0x458 [ath11k]
 ath11k_dp_rx_process_mon_rings+0x310/0x4c0 [ath11k]
 ath11k_dp_service_srng+0x234/0x338 [ath11k]
 ath11k_pcic_ext_grp_napi_poll+0x30/0xb8 [ath11k]
 __napi_poll+0x5c/0x190
 napi_threaded_poll+0xf0/0x118
 kthread+0xf4/0x110
 ret_from_fork+0x10/0x20

Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1
Reported-by: Florian Schmidt <florian at fls.name>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216573
Signed-off-by: Nagarajan Maran <quic_nmaran at quicinc.com>
---
 drivers/net/wireless/ath/ath11k/dp_rx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
index c5a4c34d7749..2c2b9da37b3f 100644
--- a/drivers/net/wireless/ath/ath11k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
@@ -5022,6 +5022,7 @@ static int ath11k_dp_rx_mon_deliver(struct ath11k *ar, u32 mac_id,
 		} else {
 			rxs->flag |= RX_FLAG_ALLOW_SAME_PN;
 		}
+		rxs->flag |= RX_FLAG_ONLY_MONITOR;
 		ath11k_update_radiotap(ar, ppduinfo, mon_skb, rxs);
 
 		ath11k_dp_rx_deliver_msdu(ar, napi, mon_skb, rxs);
-- 
2.17.1