2022-02-10 17:54:49

by Tom Rix

Subject: [PATCH] drm/amdkfd: fix loop error handling

From: Tom Rix <[email protected]>

Clang static analysis reports this problem
kfd_chardev.c:2594:16: warning: The expression is an uninitialized value.
The computed value will also be garbage
while (ret && i--) {
^~~

i is a loop variable and this block unwinds a problem in the loop.
When the error happens before the loop, this value is garbage.
Move the initialization of i to its decalaration.

Fixes: be072b06c739 ("drm/amdkfd: CRIU export BOs as prime dmabuf objects")
Signed-off-by: Tom Rix <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 636391c61cafb..4310ca07af130 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -2374,7 +2374,7 @@ static int criu_restore_bos(struct kfd_process *p,
const bool criu_resume = true;
bool flush_tlbs = false;
int ret = 0, j = 0;
- uint32_t i;
+ uint32_t i = 0;

if (*priv_offset + (args->num_bos * sizeof(*bo_privs)) > max_priv_data_size)
return -EINVAL;
@@ -2410,7 +2410,7 @@ static int criu_restore_bos(struct kfd_process *p,
*priv_offset += args->num_bos * sizeof(*bo_privs);

/* Create and map new BOs */
- for (i = 0; i < args->num_bos; i++) {
+ for (; i < args->num_bos; i++) {
struct kfd_criu_bo_bucket *bo_bucket;
struct kfd_criu_bo_priv_data *bo_priv;
struct kfd_dev *dev;
--
2.26.3

2022-02-11 10:34:57

by Felix Kuehling

Subject: Re: [PATCH] drm/amdkfd: fix loop error handling

Am 2022-02-10 um 12:04 schrieb [email protected]:
> From: Tom Rix <[email protected]>
>
> Clang static analysis reports this problem
> kfd_chardev.c:2594:16: warning: The expression is an uninitialized value.
> The computed value will also be garbage
> while (ret && i--) {
> ^~~
>
> i is a loop variable and this block unwinds a problem in the loop.
> When the error happens before the loop, this value is garbage.
> Move the initialization of i to its decalaration.
>
> Fixes: be072b06c739 ("drm/amdkfd: CRIU export BOs as prime dmabuf objects")
> Signed-off-by: Tom Rix <[email protected]>

Thank you. I applied the patch to amd-staging-drm-next.

Regards,
  Felix


> ---
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 636391c61cafb..4310ca07af130 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -2374,7 +2374,7 @@ static int criu_restore_bos(struct kfd_process *p,
> const bool criu_resume = true;
> bool flush_tlbs = false;
> int ret = 0, j = 0;
> - uint32_t i;
> + uint32_t i = 0;
>
> if (*priv_offset + (args->num_bos * sizeof(*bo_privs)) > max_priv_data_size)
> return -EINVAL;
> @@ -2410,7 +2410,7 @@ static int criu_restore_bos(struct kfd_process *p,
> *priv_offset += args->num_bos * sizeof(*bo_privs);
>
> /* Create and map new BOs */
> - for (i = 0; i < args->num_bos; i++) {
> + for (; i < args->num_bos; i++) {
> struct kfd_criu_bo_bucket *bo_bucket;
> struct kfd_criu_bo_priv_data *bo_priv;
> struct kfd_dev *dev;