smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com --- drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj); + struct dma_buf *dmabuf;
if (obj->import_attach) { /* DMABUF/PRIME Path */ + dmabuf = obj->import_attach->dmabuf; dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); - dma_buf_put(obj->import_attach->dmabuf); + dma_buf_put(dmabuf); } else { /* Private buffer allocation path */ qaic_free_sgt(bo->sgt);
Am 10.06.23 um 04:12 schrieb Sukrut Bellary:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj);
- struct dma_buf *dmabuf;
Maybe move that variable into the if.
if (obj->import_attach) { /* DMABUF/PRIME Path */
dmabuf = obj->import_attach->dmabuf;
dma_buf_put(obj->import_attach->dmabuf);
dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
} else { /* Private buffer allocation path */ qaic_free_sgt(bo->sgt);
On 6/12/2023 4:52 PM, Christian König wrote:
Am 10.06.23 um 04:12 schrieb Sukrut Bellary:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj); + struct dma_buf *dmabuf;
Maybe move that variable into the if.
if (obj->import_attach) { /* DMABUF/PRIME Path */ + dmabuf = obj->import_attach->dmabuf; dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); - dma_buf_put(obj->import_attach->dmabuf); + dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
Driver uses drm_gem_prime_fd_to_handle() helper function but it also registers for ->gem_prime_import() which is internally called by drm_gem_prime_fd_to_handle(). All the operations done in gem_prime_import() are undone here.
} else { /* Private buffer allocation path */ qaic_free_sgt(bo->sgt);
Am 12.06.23 um 15:03 schrieb Pranjal Ramajor Asha Kanojiya:
On 6/12/2023 4:52 PM, Christian König wrote:
Am 10.06.23 um 04:12 schrieb Sukrut Bellary:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj); + struct dma_buf *dmabuf;
Maybe move that variable into the if.
if (obj->import_attach) { /* DMABUF/PRIME Path */ + dmabuf = obj->import_attach->dmabuf; dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); - dma_buf_put(obj->import_attach->dmabuf); + dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
Driver uses drm_gem_prime_fd_to_handle() helper function but it also registers for ->gem_prime_import() which is internally called by drm_gem_prime_fd_to_handle(). All the operations done in gem_prime_import() are undone here.
Then why don't you use drm_prime_gem_destroy() which is the cleanup helper for imports created by ->gem_prime_import() ?
That looks pretty much identical to what you do here manually.
Regards, Christian.
} else { /* Private buffer allocation path */ qaic_free_sgt(bo->sgt);
On 6/12/2023 7:21 AM, Christian König wrote:
Am 12.06.23 um 15:03 schrieb Pranjal Ramajor Asha Kanojiya:
On 6/12/2023 4:52 PM, Christian König wrote:
Am 10.06.23 um 04:12 schrieb Sukrut Bellary:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj); + struct dma_buf *dmabuf;
Maybe move that variable into the if.
if (obj->import_attach) { /* DMABUF/PRIME Path */ + dmabuf = obj->import_attach->dmabuf; dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); - dma_buf_put(obj->import_attach->dmabuf); + dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
Driver uses drm_gem_prime_fd_to_handle() helper function but it also registers for ->gem_prime_import() which is internally called by drm_gem_prime_fd_to_handle(). All the operations done in gem_prime_import() are undone here.
Then why don't you use drm_prime_gem_destroy() which is the cleanup helper for imports created by ->gem_prime_import() ?
That looks pretty much identical to what you do here manually.
I think destroy() wasn't used because we are new to DRM and sometimes confused by the multitude of options. I appreciate the suggestion and will follow up to see if destroy() will work here, or identify what would prevent the use of it.
-Jeff
On 6/12/2023 8:39 PM, Jeffrey Hugo wrote:
On 6/12/2023 7:21 AM, Christian König wrote:
Am 12.06.23 um 15:03 schrieb Pranjal Ramajor Asha Kanojiya:
On 6/12/2023 4:52 PM, Christian König wrote:
Am 10.06.23 um 04:12 schrieb Sukrut Bellary:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj); + struct dma_buf *dmabuf;
Maybe move that variable into the if.
if (obj->import_attach) { /* DMABUF/PRIME Path */ + dmabuf = obj->import_attach->dmabuf; dma_buf_detach(obj->import_attach->dmabuf, obj->import_attach); - dma_buf_put(obj->import_attach->dmabuf); + dma_buf_put(dmabuf);
I strongly assume you are not using the GEM prime helpers for this?
Christian.
Driver uses drm_gem_prime_fd_to_handle() helper function but it also registers for ->gem_prime_import() which is internally called by drm_gem_prime_fd_to_handle(). All the operations done in gem_prime_import() are undone here.
Then why don't you use drm_prime_gem_destroy() which is the cleanup helper for imports created by ->gem_prime_import() ?
That looks pretty much identical to what you do here manually.
I think destroy() wasn't used because we are new to DRM and sometimes confused by the multitude of options. I appreciate the suggestion and will follow up to see if destroy() will work here, or identify what would prevent the use of it.
-Jeff
Thank you Christian for your suggestion. I agree with you driver can use drm_prime_gem_destroy() here.
On 6/10/2023 7:42 AM, Sukrut Bellary wrote:
smatch warning: drivers/accel/qaic/qaic_data.c:620 qaic_free_object() error: dereferencing freed memory 'obj->import_attach'
obj->import_attach is detached and freed using dma_buf_detach(). But used after free to decrease the dmabuf ref count using dma_buf_put().
Fixes: ff13be830333 ("accel/qaic: Add datapath") Signed-off-by: Sukrut Bellary sukrut.bellary@linux.com
drivers/accel/qaic/qaic_data.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c index e42c1f9ffff8..7cba4d680ea8 100644 --- a/drivers/accel/qaic/qaic_data.c +++ b/drivers/accel/qaic/qaic_data.c @@ -613,11 +613,13 @@ static int qaic_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struc static void qaic_free_object(struct drm_gem_object *obj) { struct qaic_bo *bo = to_qaic_bo(obj);
- struct dma_buf *dmabuf;
if (obj->import_attach) { /* DMABUF/PRIME Path */
dmabuf = obj->import_attach->dmabuf;
dma_buf_put(obj->import_attach->dmabuf);
dma_buf_put(dmabuf);
Reviewed-by: Pranjal Ramajor Asha Kanojiya quic_pkanojiy@quicinc.com
linaro-mm-sig@lists.linaro.org
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Christian König -
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Pranjal Ramajor Asha Kanojiya -
Sukrut Bellary