wifi: iwlwifi: debug: fix crash in __iwl_err()

[ Upstream commit 634c7b1 ]

In __iwl_err(), if we rate-limit the message away, then
vaf.va is still NULL-initialized by the time we get to
the tracing code, which then crashes. When it doesn't
get rate-limited out, it's still wrong to reuse the old
args2 that was already printed, which is why we bother
making a copy in the first place.

Assign vaf.va properly to fix this.

Fixes: e5f1cc9 ("iwlwifi: allow rate-limited error messages")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230413102635.e27134c6bcd4.Ib3894cd2ba7a5ad5e75912a7634f146ceaa569e2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/wireless/intel/iwlwifi/iwl-debug.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright (C) 2005-2011, 2021 Intel Corporation
+ * Copyright (C) 2005-2011, 2021-2022 Intel Corporation
  */
 #include <linux/device.h>
 #include <linux/interrupt.h>
@@ -57,6 +57,7 @@ void __iwl_err(struct device *dev, enum iwl_err_mode mode, const char *fmt, ...)
 	default:
 		break;
 	}
+	vaf.va = &args;
 	trace_iwlwifi_err(&vaf);
 	va_end(args);
 }