[PATCH v3 4.19.y-cip 17/17] spi: rpc-if: Fix use-after-free on unbind

Lad Prabhakar

From: Lukas Wunner <lukas@...>

commit 393f981ca5f797b58b882d42b7621fb6e43c7f5b upstream.

rpcif_spi_remove() accesses the driver's private data after calling
spi_unregister_controller() even though that function releases the last
reference on the spi_controller and thereby frees the private data.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound.

Fixes: eb8d6d464a27 ("spi: add Renesas RPC-IF driver")
Signed-off-by: Lukas Wunner <lukas@...>
Cc: <stable@...> # v5.9+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@...> # v5.9+
Cc: Sergei Shtylyov <s.shtylyov@...>
Link: https://lore.kernel.org/r/c5da472c28021da2f6517441685cef033d40b140.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@...>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...>
drivers/spi/spi-rpc-if.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-rpc-if.c b/drivers/spi/spi-rpc-if.c
index ed3e548227f4..3579675485a5 100644
--- a/drivers/spi/spi-rpc-if.c
+++ b/drivers/spi/spi-rpc-if.c
@@ -134,7 +134,7 @@ static int rpcif_spi_probe(struct platform_device *pdev)
struct rpcif *rpc;
int error;

- ctlr = spi_alloc_master(&pdev->dev, sizeof(*rpc));
+ ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*rpc));
if (!ctlr)
return -ENOMEM;

@@ -159,13 +159,8 @@ static int rpcif_spi_probe(struct platform_device *pdev)
error = spi_register_controller(ctlr);
if (error) {
dev_err(&pdev->dev, "spi_register_controller failed\n");
- goto err_put_ctlr;
+ rpcif_disable_rpm(rpc);
- return 0;
- rpcif_disable_rpm(rpc);
- spi_controller_put(ctlr);

return error;

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