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From: Su Hui <suhui@nfschina.com>
To: srinivas.pandruvada@linux.intel.com,
	hdegoede@redhat.com,
	ilpo.jarvinen@linux.intel.com,
	nathan@kernel.org,
	ndesaulniers@google.com,
	morbo@google.com,
	justinstitt@google.com
Cc: Su Hui <suhui@nfschina.com>,
	rui.zhang@intel.com,
	platform-driver-x86@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] platform/x86: ISST: fix use after free problem in tpmi_sst_dev_remove()
Date: Mon, 20 May 2024 10:19:35 +0800
Message-Id: <20240520021934.113877-1-suhui@nfschina.com>
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clang static checker (scan-build) warning:
drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c:1614:24:
Use of memory after it is freed.

Using 'tpmi_sst->package_id' after releasing 'tpmi_sst' causes this
problem. Change the order of releasing 'tpmi_sst' to fix this.

Fixes: 9d1d36268f3d ("platform/x86: ISST: Support partitioned systems")
Signed-off-by: Su Hui <suhui@nfschina.com>
---
 drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
index 7bac7841ff0a..7fa360073f6e 100644
--- a/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
+++ b/drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c
@@ -1610,8 +1610,8 @@ void tpmi_sst_dev_remove(struct auxiliary_device *auxdev)
 	tpmi_sst->partition_mask_current &= ~BIT(plat_info->partition);
 	/* Free the package instance when the all partitions are removed */
 	if (!tpmi_sst->partition_mask_current) {
-		kfree(tpmi_sst);
 		isst_common.sst_inst[tpmi_sst->package_id] = NULL;
+		kfree(tpmi_sst);
 	}
 	mutex_unlock(&isst_tpmi_dev_lock);
 }
-- 
2.30.2