Messages in this thread Patch in this message |  | | From | trix@redhat ... | Subject | [PATCH v2] bus: fsl-mc: fix invalid free in fsl_mc_device_add | Date | Thu, 9 Jul 2020 05:41:15 -0700 |
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From: Tom Rix <trix@redhat.com>
clang static analysis flags this error
fsl-mc-bus.c:695:2: warning: Attempt to free released memory [unix.Malloc] kfree(mc_dev); ^~~~~~~~~~~~~
The problem block of code is
mc_bus = kzalloc(sizeof(*mc_bus), GFP_KERNEL); if (!mc_bus) return -ENOMEM;
mc_dev = &mc_bus->mc_dev;
mc_bus's structure contains a mc_dev element, freeing it later is not appropriate.
So check if mc_bus was allocated before freeing mc_dev
This is a case where checkpatch
WARNING: kfree(NULL) is safe and this check is probably not required + if (mc_bus) + kfree(mc_bus);
is wrong.
Fixes: a042fbed0290 ("staging: fsl-mc: simplify couple of deallocations")
Signed-off-by: Tom Rix <trix@redhat.com> --- v1: add a comment to explain freeing uniqueness drivers/bus/fsl-mc/fsl-mc-bus.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 40526da5c6a6..df10ed430baa 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -691,8 +691,14 @@ 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); + /* + * mc_bus allocates a private version of mc_dev + * it is not appropriate to free the private version. + */ + if (mc_bus) + kfree(mc_bus); + else + kfree(mc_dev); return error; } -- 2.18.1
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