[PATCH 1/2] wifi: ath12k: fix crash when unbinding

[Jose Ignacio Tornos Martinez <jtornosm@redhat.com>]

If there is an error during some initialization realated to firmware,
the funcion ath12k_dp_cc_cleanup is already call to release resources.
However this is released again when the device is unbinded (ath12k_pci),
and we get:
[  382.050650] BUG: kernel NULL pointer dereference, address: 0000000000000020
[  382.050656] #PF: supervisor read access in kernel mode
[  382.050657] #PF: error_code(0x0000) - not-present page
[  382.050659] PGD 0 P4D 0
[  382.050661] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
[  382.050664] CPU: 0 UID: 0 PID: 6541 Comm: bash Kdump: loaded Not tainted 6.12.0-rc1+ #14
[  382.050666] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
[  382.050667] RIP: 0010:ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k]
[  382.050688] Code: 8b 76 28 48 8b 7b 10 45 31 c0 b9 02 00 00 00 e8 30 3d 35 c2 be 02 00 00 00 4c 89 f7 e8 e3 00 fb c2 49 83 c7 28 49 39 ef 74 31 <41> f6 47 20 01 75 ab 4c 89 ff e8 2b de a2 c2 84 c0 74 0e 49 8b 17
[  382.050689] RSP: 0018:ffffa3e3c0e83990 EFLAGS: 00010297
[  382.050691] RAX: 0000000000000000 RBX: ffff90de08750000 RCX: 0000000000000000
[  382.050692] RDX: 0000000000000001 RSI: ffff90de08751178 RDI: ffff90de08751970
[  382.050693] RBP: 0000000000005000 R08: 0000000000000200 R09: 000000000040003f
[  382.050694] R10: 000000000040003f R11: 0000000000000000 R12: dead000000000122
[  382.050695] R13: dead000000000100 R14: ffffffffc0b6f948 R15: 0000000000000000
[  382.050696] FS:  00007f216b1ab740(0000) GS:ffff90de5fc00000(0000) knlGS:0000000000000000
[  382.050698] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  382.050699] CR2: 0000000000000020 CR3: 000000001a26c000 CR4: 0000000000752ef0
[  382.050702] PKRU: 55555554
[  382.050703] Call Trace:
[  382.050705]  <TASK>
[  382.050707]  ? __die_body.cold+0x19/0x27
[  382.050719]  ? page_fault_oops+0x15a/0x2f0
[  382.050723]  ? exc_page_fault+0x7e/0x180
[  382.050724]  ? asm_exc_page_fault+0x26/0x30
[  382.050729]  ? ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k]
[  382.050740]  ? delay_halt_tpause+0x1a/0x20
[  382.050742]  ath12k_dp_free+0x67/0x110 [ath12k]
[  382.050753]  ath12k_core_deinit+0x8d/0xb0 [ath12k]
[  382.050762]  ath12k_pci_remove+0x50/0xf0 [ath12k]
[  382.050771]  pci_device_remove+0x3f/0xb0
[  382.050773]  device_release_driver_internal+0x19c/0x200
[  382.050777]  unbind_store+0xa1/0xb0
...

The issue is always reproducible from a VM because the MSI addressing
initialization is failing.

In order to fix the issue, just set to NULL the relaeased structure in
ath12k_dp_cc_cleanup at the end.

cc: stable@vger.kernel.org
Fixes: d889913205cf7 ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
---
 drivers/net/wireless/ath/ath12k/dp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/ath12k/dp.c b/drivers/net/wireless/ath/ath12k/dp.c
index 61aa78d8bd8c..789d430e4455 100644
--- a/drivers/net/wireless/ath/ath12k/dp.c
+++ b/drivers/net/wireless/ath/ath12k/dp.c
@@ -1241,6 +1241,7 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
 	}
 
 	kfree(dp->spt_info);
+	dp->spt_info = NULL;
 }
 
 static void ath12k_dp_reoq_lut_cleanup(struct ath12k_base *ab)
-- 
2.46.2