[PATCH v4 0/3] venus: core: add shutdown callback for venus

[PATCH v4 0/3] venus: core: add shutdown callback for venus

[Mansur Alisha Shaik]

Add shutdown callback for venus driver.
Handle race conditions in concurrency usecases like
multiple browser YouTube browser tabs(approx 50 tabs)
graphics_Stress, WiFi ON/OFF, Bluetooth ON/OF,
and reboot in parallel.

Mansur Alisha Shaik (3):
  venus: core: handle race condititon for core ops
  venus: handle use after free for iommu_map/iommu_unmap
  venus: core: add shutdown callback for venus

 drivers/media/platform/qcom/venus/core.c     |  9 +++++++++
 drivers/media/platform/qcom/venus/firmware.c | 17 +++++++++++++----
 drivers/media/platform/qcom/venus/hfi.c      | 17 ++++++++++++++++-
 3 files changed, 38 insertions(+), 5 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v4 1/3] venus: core: handle race condititon for core ops

[Mansur Alisha Shaik]

For core ops we are having only write protect but there
is no read protect, because of this in multthreading
and concurrency, one CPU core is reading without wait
which is causing the NULL pointer dereferece crash.

one such scenario is as show below, where in one CPU
core, core->ops becoming NULL and in another CPU core
calling core->ops->session_init().

CPU: core-7:
Call trace:
 hfi_session_init+0x180/0x1dc [venus_core]
 vdec_queue_setup+0x9c/0x364 [venus_dec]
 vb2_core_reqbufs+0x1e4/0x368 [videobuf2_common]
 vb2_reqbufs+0x4c/0x64 [videobuf2_v4l2]
 v4l2_m2m_reqbufs+0x50/0x84 [v4l2_mem2mem]
 v4l2_m2m_ioctl_reqbufs+0x2c/0x38 [v4l2_mem2mem]
 v4l_reqbufs+0x4c/0x5c
__video_do_ioctl+0x2b0/0x39c

CPU: core-0:
Call trace:
 venus_shutdown+0x98/0xfc [venus_core]
 venus_sys_error_handler+0x64/0x148 [venus_core]
 process_one_work+0x210/0x3d0
 worker_thread+0x248/0x3f4
 kthread+0x11c/0x12c

Signed-off-by: Mansur Alisha Shaik <mansur@codeaurora.org>
Acked-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
---
Changes in V4:
- Addressed review comments by Stan in patch series 
  https://lore.kernel.org/patchwork/patch/1303678/
  and combining this change along with shutdown callback
  as we are facing race conditions with shutdown callback

 drivers/media/platform/qcom/venus/hfi.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c
index a59022a..58d4c06 100644
--- a/drivers/media/platform/qcom/venus/hfi.c
+++ b/drivers/media/platform/qcom/venus/hfi.c
@@ -195,19 +195,34 @@ EXPORT_SYMBOL_GPL(hfi_session_create);
 int hfi_session_init(struct venus_inst *inst, u32 pixfmt)
 {
 	struct venus_core *core = inst->core;
-	const struct hfi_ops *ops = core->ops;
+	const struct hfi_ops *ops;
 	int ret;
 
+	/*
+	 * If core shutdown is in progress or if we are in system
+	 * recovery, return an error as during system error recovery
+	 * session_init() can't pass successfully
+	 */
+	mutex_lock(&core->lock);
+	if (!core->ops || core->sys_error) {
+		mutex_unlock(&core->lock);
+		return -EIO;
+	}
+	mutex_unlock(&core->lock);
+
 	if (inst->state != INST_UNINIT)
 		return -EINVAL;
 
 	inst->hfi_codec = to_codec_type(pixfmt);
 	reinit_completion(&inst->done);
 
+	mutex_lock(&core->lock);
+	ops = core->ops;
 	ret = ops->session_init(inst, inst->session_type, inst->hfi_codec);
 	if (ret)
 		return ret;
 
+	mutex_unlock(&core->lock);
 	ret = wait_session_msg(inst);
 	if (ret)
 		return ret;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH v4 1/3] venus: core: handle race condititon for core ops

[Stanimir Varbanov]

On 9/16/20 11:49 AM, Mansur Alisha Shaik wrote:
> For core ops we are having only write protect but there
> is no read protect, because of this in multthreading
> and concurrency, one CPU core is reading without wait
> which is causing the NULL pointer dereferece crash.
> 
> one such scenario is as show below, where in one CPU
> core, core->ops becoming NULL and in another CPU core
> calling core->ops->session_init().
> 
> CPU: core-7:
> Call trace:
>  hfi_session_init+0x180/0x1dc [venus_core]
>  vdec_queue_setup+0x9c/0x364 [venus_dec]
>  vb2_core_reqbufs+0x1e4/0x368 [videobuf2_common]
>  vb2_reqbufs+0x4c/0x64 [videobuf2_v4l2]
>  v4l2_m2m_reqbufs+0x50/0x84 [v4l2_mem2mem]
>  v4l2_m2m_ioctl_reqbufs+0x2c/0x38 [v4l2_mem2mem]
>  v4l_reqbufs+0x4c/0x5c
> __video_do_ioctl+0x2b0/0x39c
> 
> CPU: core-0:
> Call trace:
>  venus_shutdown+0x98/0xfc [venus_core]
>  venus_sys_error_handler+0x64/0x148 [venus_core]
>  process_one_work+0x210/0x3d0
>  worker_thread+0x248/0x3f4
>  kthread+0x11c/0x12c
> 
> Signed-off-by: Mansur Alisha Shaik <mansur@codeaurora.org>
> Acked-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
> ---
> Changes in V4:
> - Addressed review comments by Stan in patch series 
>   https://lore.kernel.org/patchwork/patch/1303678/
>   and combining this change along with shutdown callback
>   as we are facing race conditions with shutdown callback
> 
>  drivers/media/platform/qcom/venus/hfi.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c
> index a59022a..58d4c06 100644
> --- a/drivers/media/platform/qcom/venus/hfi.c
> +++ b/drivers/media/platform/qcom/venus/hfi.c
> @@ -195,19 +195,34 @@ EXPORT_SYMBOL_GPL(hfi_session_create);
>  int hfi_session_init(struct venus_inst *inst, u32 pixfmt)
>  {
>  	struct venus_core *core = inst->core;
> -	const struct hfi_ops *ops = core->ops;
> +	const struct hfi_ops *ops;
>  	int ret;
>  
> +	/*
> +	 * If core shutdown is in progress or if we are in system
> +	 * recovery, return an error as during system error recovery
> +	 * session_init() can't pass successfully
> +	 */
> +	mutex_lock(&core->lock);
> +	if (!core->ops || core->sys_error) {
> +		mutex_unlock(&core->lock);
> +		return -EIO;
> +	}
> +	mutex_unlock(&core->lock);
> +
>  	if (inst->state != INST_UNINIT)
>  		return -EINVAL;
>  
>  	inst->hfi_codec = to_codec_type(pixfmt);
>  	reinit_completion(&inst->done);
>  
> +	mutex_lock(&core->lock);
> +	ops = core->ops;

This is not needed because we check core->ops for NULL under mutex held
at the beginning of the function. Just keep ops initialization as it is
in the original code.

>  	ret = ops->session_init(inst, inst->session_type, inst->hfi_codec);
>  	if (ret)
>  		return ret;
>  
> +	mutex_unlock(&core->lock);
>  	ret = wait_session_msg(inst);
>  	if (ret)
>  		return ret;
> 

-- 
regards,
Stan

[PATCH v4 2/3] venus: handle use after free for iommu_map/iommu_unmap

[Mansur Alisha Shaik]

In concurrency usecase and reboot scenario we are seeing muliple
crashes related to iommu_map/iommu_unamp of core->fw.iommu_domain.

In one case we are seeing "Unable to handle kernel NULL pointer
dereference at virtual address 0000000000000008" crash, this is
because of core->fw.iommu_domain in venus_firmware_deinit() and
trying to map in venus_boot() during venus_sys_error_handler()

Call trace:
 __iommu_map+0x4c/0x348
 iommu_map+0x5c/0x70
 venus_boot+0x184/0x230 [venus_core]
 venus_sys_error_handler+0xa0/0x14c [venus_core]
 process_one_work+0x210/0x3d0
 worker_thread+0x248/0x3f4
 kthread+0x11c/0x12c
 ret_from_fork+0x10/0x18

In second case we are seeing "Unable to handle kernel paging request
at virtual address 006b6b6b6b6b6b9b" crash, this is because of
unmappin iommu domain which is already unmapped.

Call trace:
 venus_remove+0xf8/0x108 [venus_core]
 venus_core_shutdown+0x1c/0x34 [venus_core]
 platform_drv_shutdown+0x28/0x34
 device_shutdown+0x154/0x1fc
 kernel_restart_prepare+0x40/0x4c
 kernel_restart+0x1c/0x64
 __arm64_sys_reboot+0x190/0x238
 el0_svc_common+0xa4/0x154
 el0_svc_compat_handler+0x2c/0x38
 el0_svc_compat+0x8/0x10

Signed-off-by: Mansur Alisha Shaik <mansur@codeaurora.org>
---
 drivers/media/platform/qcom/venus/firmware.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/firmware.c b/drivers/media/platform/qcom/venus/firmware.c
index 1db64a8..d03e2dd 100644
--- a/drivers/media/platform/qcom/venus/firmware.c
+++ b/drivers/media/platform/qcom/venus/firmware.c
@@ -171,9 +171,14 @@ static int venus_shutdown_no_tz(struct venus_core *core)
 
 	iommu = core->fw.iommu_domain;
 
-	unmapped = iommu_unmap(iommu, VENUS_FW_START_ADDR, mapped);
-	if (unmapped != mapped)
-		dev_err(dev, "failed to unmap firmware\n");
+	if (core->fw.mapped_mem_size && iommu) {
+		unmapped = iommu_unmap(iommu, VENUS_FW_START_ADDR, mapped);
+
+		if (unmapped != mapped)
+			dev_err(dev, "failed to unmap firmware\n");
+		else
+			core->fw.mapped_mem_size = 0;
+	}
 
 	return 0;
 }
@@ -305,7 +310,11 @@ void venus_firmware_deinit(struct venus_core *core)
 	iommu = core->fw.iommu_domain;
 
 	iommu_detach_device(iommu, core->fw.dev);
-	iommu_domain_free(iommu);
+
+	if (core->fw.iommu_domain) {
+		iommu_domain_free(iommu);
+		core->fw.iommu_domain = NULL;
+	}
 
 	platform_device_unregister(to_platform_device(core->fw.dev));
 }
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v4 3/3] venus: core: add shutdown callback for venus

[Mansur Alisha Shaik]

After the SMMU translation is disabled in the
arm-smmu shutdown callback during reboot, if
any subsystem are still alive then IOVAs they
are using will become PAs on bus, which may
lead to crash.

So implemented shutdown callback, which detach iommu maps.

Signed-off-by: Mansur Alisha Shaik <mansur@codeaurora.org>
Acked-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
---
Changes in V4:
- In venus_core_shutdown(), instead of venurs_remove() calling 
  venus_shutdown() and venus_firmware_deinit().
- With venus_remove() call during shutdown we are facing few issue 
  like ui freez this is because in venus_remove, hfi_core_deinit()
  will wait until all core instances count become zero dudring 
  wait_var_event().

Changes in V3:
- Fix build errors

 drivers/media/platform/qcom/venus/core.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c
index 6103aaf..65b71ac 100644
--- a/drivers/media/platform/qcom/venus/core.c
+++ b/drivers/media/platform/qcom/venus/core.c
@@ -345,6 +345,14 @@ static int venus_remove(struct platform_device *pdev)
 	return ret;
 }
 
+static void venus_core_shutdown(struct platform_device *pdev)
+{
+	struct venus_core *core = platform_get_drvdata(pdev);
+
+	venus_shutdown(core);
+	venus_firmware_deinit(core);
+}
+
 static __maybe_unused int venus_runtime_suspend(struct device *dev)
 {
 	struct venus_core *core = dev_get_drvdata(dev);
@@ -602,6 +610,7 @@ static struct platform_driver qcom_venus_driver = {
 		.of_match_table = venus_dt_match,
 		.pm = &venus_pm_ops,
 	},
+	.shutdown = venus_core_shutdown,
 };
 module_platform_driver(qcom_venus_driver);
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation