[PATCH v2] block: mtip32xx: Prioritize state cleanup over memory freeing in the mtip_pci_probe error path.

[Zhang Heng]

The original sequence kfree(dd); pci_set_drvdata(pdev, NULL); creates a
theoretical race condition window. Between these two calls, the pci_dev
structure retains a dangling pointer to the already-freed device private
data (dd). Any concurrent access to the drvdata (e.g., from an interrupt
handler or an unexpected call to remove) would lead to a use-after-free
kernel oops.

Changes made:
1. `pci_set_drvdata(pdev, NULL);` - First, atomically sever the link
from the pci_dev.
2. `kfree(dd);` - Then, safely free the private memory.

This ensures the kernel state is always consistent before resources
are released, adhering to defensive programming principles.

Signed-off-by: Zhang Heng <zhangheng@xxxxxxxxxx>
---
 drivers/block/mtip32xx/mtip32xx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 8fc7761397bd..f228363e6b1c 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3839,9 +3839,8 @@ static int mtip_pci_probe(struct pci_dev *pdev,
 	}
 
 iomap_err:
-	kfree(dd);
 	pci_set_drvdata(pdev, NULL);
-	return rv;
+	kfree(dd);
 done:
 	return rv;
 }
-- 
2.47.1