Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
The function then returns non-zero value, which causes the second deallocation.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
Signed-off-by: Daniil Dulov <[email protected]>
---
drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
index 3b6f5963180d..bce11c5b07d6 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
@@ -119,7 +119,8 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
}
if (retval) {
- kfree(mqd_mem_obj);
+ if (mqd_mem_obj)
+ kfree(mqd_mem_obj);
return NULL;
}
--
2.25.1
Hi Daniil,
On Mon, Apr 17, 2023 at 11:55:21PM -0700, Daniil Dulov wrote:
> Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
> The function then returns non-zero value, which causes the second deallocation.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
> Signed-off-by: Daniil Dulov <[email protected]>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> index 3b6f5963180d..bce11c5b07d6 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> @@ -119,7 +119,8 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
> }
>
> if (retval) {
> - kfree(mqd_mem_obj);
> + if (mqd_mem_obj)
> + kfree(mqd_mem_obj);
I think this is not needed. kfree() returns immediately if
mqd_mem_obj is NULL.
Andi
> return NULL;
> }
>
> --
> 2.25.1
On 18/04/2023 10:47, Andi Shyti wrote:
> Hi Daniil,
>
> On Mon, Apr 17, 2023 at 11:55:21PM -0700, Daniil Dulov wrote:
>> Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
>> The function then returns non-zero value, which causes the second deallocation.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
>> Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
>> Signed-off-by: Daniil Dulov <[email protected]>
>> ---
>> drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
>> index 3b6f5963180d..bce11c5b07d6 100644
>> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
>> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
>> @@ -119,7 +119,8 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
>> }
>>
>> if (retval) {
>> - kfree(mqd_mem_obj);
>> + if (mqd_mem_obj)
>> + kfree(mqd_mem_obj);
>
> I think this is not needed. kfree() returns immediately if
> mqd_mem_obj is NULL.
>
Yep, the tool has to be fixed because such patch is just misleading.
However different point - the commit description actually describes
entirely different case: double free. Maybe the issue is true, just the
fix is wrong?
Best regards,
Krzysztof
On Tue, Apr 18, 2023 at 12:07:15PM +0200, Krzysztof Kozlowski wrote:
> On 18/04/2023 10:47, Andi Shyti wrote:
> > Hi Daniil,
> >
> > On Mon, Apr 17, 2023 at 11:55:21PM -0700, Daniil Dulov wrote:
> >> Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
> >> The function then returns non-zero value, which causes the second deallocation.
> >>
> >> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >>
> >> Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
> >> Signed-off-by: Daniil Dulov <[email protected]>
> >> ---
> >> drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> >> index 3b6f5963180d..bce11c5b07d6 100644
> >> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> >> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> >> @@ -119,7 +119,8 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
> >> }
> >>
> >> if (retval) {
> >> - kfree(mqd_mem_obj);
> >> + if (mqd_mem_obj)
> >> + kfree(mqd_mem_obj);
> >
> > I think this is not needed. kfree() returns immediately if
> > mqd_mem_obj is NULL.
> >
>
> Yep, the tool has to be fixed because such patch is just misleading.
> However different point - the commit description actually describes
> entirely different case: double free. Maybe the issue is true, just the
> fix is wrong?
Yes, indeed, the fix is wrong, but the bug exists. I'm pasting
the original function:
if (kfd->cwsr_enabled && (q->type == KFD_QUEUE_TYPE_COMPUTE)) {
mqd_mem_obj = kzalloc(sizeof(struct kfd_mem_obj), GFP_KERNEL);
if (!mqd_mem_obj)
return NULL;
...
} else {
retval = kfd_gtt_sa_allocate(kfd, sizeof(struct v9_mqd),
&mqd_mem_obj);
}
if (retval) {
kfree(mqd_mem_obj);
return NULL;
}
The "kfd_gtt_sa_allocate()" function allocates mqd_mem_obj and if
an error occurs internally frees it, without setting it to NULL;
retval is true and we kfree a memory that has already been freed.
The real fix is to move the "if (retval)" inside the if. It would
basically be:
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
index fdbfd725841ff..31d47d687bd62 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
@@ -115,18 +115,20 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
&(mqd_mem_obj->gtt_mem),
&(mqd_mem_obj->gpu_addr),
(void *)&(mqd_mem_obj->cpu_ptr), true);
+
+ if (retval) {
+ kfree(mqd_mem_obj);
+ return NULL;
+ }
+
} else {
retval = kfd_gtt_sa_allocate(kfd, sizeof(struct v9_mqd),
&mqd_mem_obj);
- }
-
- if (retval) {
- kfree(mqd_mem_obj);
- return NULL;
+ if (retval)
+ return NULL;
}
return mqd_mem_obj;
-
}
Maybe with some clever refactoring we could reduce some code
duplication.
Daniil will you look into this?
Andi
> Daniil will you look into this?
and, because this is a bug fix, if you do want to send a real
fix, plase add to the commit message:
Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
Cc: Oak Zeng <[email protected]>
Cc: <[email protected]> # v5.3+
Andi
PS: please note that Oak's e-mail has changed.
Thank you for your feedback! I will do it as soon as possible.
Daniil
________________________________
От: Andi Shyti <[email protected]>
Отправлено: вторник, 18 апреля 2023 г., 20:44
Кому: Andi Shyti <[email protected]>
Копия: Krzysztof Kozlowski <[email protected]>; Daniil Dulov <[email protected]>; Felix Kuehling <[email protected]>; [email protected] <[email protected]>; David Airlie <[email protected]>; [email protected] <[email protected]>; [email protected] <[email protected]>; [email protected] <[email protected]>; Alex Deucher <[email protected]>; Oak Zeng <[email protected]>; Christian König <[email protected]>
Тема: Re: [PATCH] drm/amdkfd: Fix potential deallocation of previously deallocated memory.
> Daniil will you look into this?
and, because this is a bug fix, if you do want to send a real
fix, plase add to the commit message:
Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
Cc: Oak Zeng <[email protected]>
Cc: <[email protected]> # v5.3+
Andi
PS: please note that Oak's e-mail has changed.
Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
The function then returns non-zero value, which causes the second deallocation.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
Signed-off-by: Daniil Dulov <[email protected]>
---
v2: Move if (retval) inside previous if as Andi Shyti <[email protected]> suggested.
drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
index 3b6f5963180d..dadeb2013fd9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
@@ -113,18 +113,19 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
&(mqd_mem_obj->gtt_mem),
&(mqd_mem_obj->gpu_addr),
(void *)&(mqd_mem_obj->cpu_ptr), true);
+
+ if (retval) {
+ kfree(mqd_mem_obj);
+ return NULL;
+ }
} else {
retval = kfd_gtt_sa_allocate(kfd, sizeof(struct v9_mqd),
&mqd_mem_obj);
- }
-
- if (retval) {
- kfree(mqd_mem_obj);
- return NULL;
+ if (retval)
+ return NULL;
}
return mqd_mem_obj;
-
}
static void init_mqd(struct mqd_manager *mm, void **mqd,
--
2.25.1
On 2023-05-11 07:23, Daniil Dulov wrote:
> Pointer mqd_mem_obj can be deallocated in kfd_gtt_sa_allocate().
> The function then returns non-zero value, which causes the second deallocation.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d1f8f0d17d40 ("drm/amdkfd: Move non-sdma mqd allocation out of init_mqd")
> Signed-off-by: Daniil Dulov <[email protected]>
Thanks. I am applying this patch to amd-staging-drm-next.
Reviewed-by: Felix Kuehling <[email protected]>
> ---
> v2: Move if (retval) inside previous if as Andi Shyti <[email protected]> suggested.
> drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> index 3b6f5963180d..dadeb2013fd9 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_v9.c
> @@ -113,18 +113,19 @@ static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
> &(mqd_mem_obj->gtt_mem),
> &(mqd_mem_obj->gpu_addr),
> (void *)&(mqd_mem_obj->cpu_ptr), true);
> +
> + if (retval) {
> + kfree(mqd_mem_obj);
> + return NULL;
> + }
> } else {
> retval = kfd_gtt_sa_allocate(kfd, sizeof(struct v9_mqd),
> &mqd_mem_obj);
> - }
> -
> - if (retval) {
> - kfree(mqd_mem_obj);
> - return NULL;
> + if (retval)
> + return NULL;
> }
>
> return mqd_mem_obj;
> -
> }
>
> static void init_mqd(struct mqd_manager *mm, void **mqd,