[PATCH v4 1/2] wifi: ath12k: fix crash when unbinding

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

If there is an error during some initialization related to firmware,
the function ath12k_dp_cc_cleanup is called to release resources.
However this is released again when the device is unbinded (ath12k_pci),
and we get:
BUG: kernel NULL pointer dereference, address: 0000000000000020
at RIP: 0010:ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k]
Call Trace:
ath12k_dp_cc_cleanup
ath12k_dp_free
ath12k_core_deinit
ath12k_pci_remove
...

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 released structure in
ath12k_dp_cc_cleanup at the end.

cc: stable@vger.kernel.org
Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
---
v4:
  - Send with cover letter to get reference with 2/2
v3: https://lore.kernel.org/linux-wireless/20241017074654.176678-1-jtornosm@redhat.com/
v2: https://lore.kernel.org/linux-wireless/20241016123452.206671-1-jtornosm@redhat.com/
v1: https://lore.kernel.org/linux-wireless/20241010175102.207324-2-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