bus: fsl-mc: fix double-free on mc_dev

[ Upstream commit d694bf8a9acdbd061596f3e7549bc8cb70750a60 ]

The blamed commit tried to simplify how the deallocations are done but,
in the process, introduced a double-free on the mc_dev variable.

In case the MC device is a DPRC, a new mc_bus is allocated and the
mc_dev variable is just a reference to one of its fields. In this
circumstance, on the error path only the mc_bus should be freed.

This commit introduces back the following checkpatch warning which is a
false-positive.

WARNING: kfree(NULL) is safe and this check is probably not required
+       if (mc_bus)
+               kfree(mc_bus);

Fixes: a042fbed0290 ("staging: fsl-mc: simplify couple of deallocations")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20250408105814.2837951-2-ioana.ciornei@nxp.com
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index e329cdd7156c980a0b1f3de884622178669f51b0..9c207f1c19fbd2b060dafe051462ccff069ee0f6 100644 (file)
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -800,8 +800,10 @@ int fsl_mc_device_add(struct fsl_mc_obj_desc *obj_desc,
 
 error_cleanup_dev:
        kfree(mc_dev->regions);
-       kfree(mc_bus);
-       kfree(mc_dev);
+       if (mc_bus)
+               kfree(mc_bus);
+       else
+               kfree(mc_dev);
 
        return error;
 }