RE: [PATCH v1 1/2] ACPI: NFIT: Fix memory leak, and local use of devm_*()
Michal Wilczynski wrote: > 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'. This analysis is incorrect devm cleans up on driver ->probe() failure in addition to ->remove(), and these error returns result in ->probe() failures. No leak, i.e. this is not a fix. The conversion to modern probe is ok if you want to resubmit that one without this intervening change.
Re: [PATCH v1 1/2] ACPI: NFIT: Fix memory leak, and local use of devm_*()
On Tue, Sep 26, 2023 at 09:45:19PM +0300, Michal Wilczynski wrote: > 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. LGTM, Reviewed-by: Andy Shevchenko -- With Best Regards, Andy Shevchenko
Re: [PATCH v1 1/2] ACPI: NFIT: Fix memory leak, and local use of devm_*()
On 9/26/23 11:45, Michal Wilczynski wrote:
> 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
> Signed-off-by: Michal Wilczynski
Reviewed-by: Dave Jiang
> ---
> 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(_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 = _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,
[PATCH v1 1/2] ACPI: NFIT: Fix memory leak, and local use of devm_*()
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
Signed-off-by: Michal Wilczynski
---
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(_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 = _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
