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From:   Michal Wilczynski <michal.wilczynski@intel.com>
To:     linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
        nvdimm@lists.linux.dev
Cc:     rafael.j.wysocki@intel.com, andriy.shevchenko@intel.com,
        lenb@kernel.org, dan.j.williams@intel.com,
        vishal.l.verma@intel.com, ira.weiny@intel.com,
        Michal Wilczynski <michal.wilczynski@intel.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: [PATCH v1 1/2] ACPI: NFIT: Fix memory leak, and local use of devm_*()
Date:   Tue, 26 Sep 2023 21:45:19 +0300
Message-ID: <20230926184520.2239723-2-michal.wilczynski@intel.com>
In-Reply-To: <20230926184520.2239723-1-michal.wilczynski@intel.com>
References: <20230926184520.2239723-1-michal.wilczynski@intel.com>
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devm_*() family of functions purpose is managing memory attached to a
device. So in general it should only be used for allocations that should
last for the whole lifecycle of the device. This is not the case for
acpi_nfit_init_interleave_set(). There are two allocations that are only
used locally in this function. What's more - if the function exits on
error path memory is never freed. It's still attached to dev and would
be freed on device detach, so this leak could be called a 'local leak'.

Fix this by switching from devm_kcalloc() to kcalloc(), and adding
proper rollback.

Fixes: eaf961536e16 ("libnvdimm, nfit: add interleave-set state-tracking infrastructure")
Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
---
 drivers/acpi/nfit/core.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index f0e6738ae3c9..78f0f855c4de 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2262,6 +2262,7 @@ static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
 	u16 nr = ndr_desc->num_mappings;
 	struct nfit_set_info2 *info2;
 	struct nfit_set_info *info;
+	int err = 0;
 	int i;
 
 	nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
@@ -2269,13 +2270,15 @@ static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
 		return -ENOMEM;
 	import_guid(&nd_set->type_guid, spa->range_guid);
 
-	info = devm_kcalloc(dev, nr, sizeof(*info), GFP_KERNEL);
+	info = kcalloc(nr, sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;
 
-	info2 = devm_kcalloc(dev, nr, sizeof(*info2), GFP_KERNEL);
-	if (!info2)
-		return -ENOMEM;
+	info2 = kcalloc(nr, sizeof(*info2), GFP_KERNEL);
+	if (!info2) {
+		err = -ENOMEM;
+		goto free_info;
+	}
 
 	for (i = 0; i < nr; i++) {
 		struct nd_mapping_desc *mapping = &ndr_desc->mapping[i];
@@ -2289,7 +2292,8 @@ static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
 
 		if (!memdev || !nfit_mem->dcr) {
 			dev_err(dev, "%s: failed to find DCR\n", __func__);
-			return -ENODEV;
+			err = -ENODEV;
+			goto free_info2;
 		}
 
 		map->region_offset = memdev->region_offset;
@@ -2337,10 +2341,13 @@ static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
 	}
 
 	ndr_desc->nd_set = nd_set;
-	devm_kfree(dev, info);
-	devm_kfree(dev, info2);
 
-	return 0;
+free_info2:
+	kfree(info2);
+free_info:
+	kfree(info);
+
+	return err;
 }
 
 static int ars_get_cap(struct acpi_nfit_desc *acpi_desc,
-- 
2.41.0