2018-07-05 16:02:36

by Loic Pallardy

[permalink] [raw]
Subject: [PATCH 1/1] remoteproc: correct rproc_free_vring() to avoid invalid kernel paging

If rproc_start() failed, rproc_resource_cleanup() is called to clean
debufs entries, then associated iommu mappings, carveouts and vdev.
Issue occurs when rproc_free_vring() is trying to reset vring resource
table entry.
At this time, table_ptr is pointing on loaded resource table and carveouts
amready released, so access to loaded resource table is generating a kernel
paging error:

[ 12.696535] Unable to handle kernel paging request at virtual address f0f357cc
[ 12.696540] pgd = (ptrval)
[ 12.696542] [f0f357cc] *pgd=6d2d0811, *pte=00000000, *ppte=00000000
[ 12.696558] Internal error: Oops: 807 [#1] SMP ARM
[ 12.696563] Modules linked in: rpmsg_core v4l2_mem2mem videobuf2_dma_contig sti_drm v4l2_common vida
[ 12.696598] CPU: 1 PID: 48 Comm: kworker/1:1 Tainted: G W 4.18.0-rc2-00018-g3170fdd-8
[ 12.696602] Hardware name: STi SoC with Flattened Device Tree
[ 12.696625] Workqueue: events request_firmware_work_func
[ 12.696659] PC is at rproc_free_vring+0x84/0xbc [remoteproc]
[ 12.696667] LR is at rproc_free_vring+0x70/0xbc [remoteproc]

This patch proposes to simply remove reset of resource table vring entries,
as firmware and resource table are reloaded at each rproc boot.
rproc_trigger_recovery() not impacted as resources not touched during recovery
procedure.

Signed-off-by: Loic Pallardy <[email protected]>
---
drivers/remoteproc/remoteproc_core.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index a9609d9..9a8b47c 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -289,16 +289,10 @@ void rproc_free_vring(struct rproc_vring *rvring)
{
int size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
struct rproc *rproc = rvring->rvdev->rproc;
- int idx = rvring->rvdev->vring - rvring;
- struct fw_rsc_vdev *rsc;

dma_free_coherent(rproc->dev.parent, size, rvring->va, rvring->dma);
idr_remove(&rproc->notifyids, rvring->notifyid);

- /* reset resource entry info */
- rsc = (void *)rproc->table_ptr + rvring->rvdev->rsc_offset;
- rsc->vring[idx].da = 0;
- rsc->vring[idx].notifyid = -1;
}

static int rproc_vdev_do_probe(struct rproc_subdev *subdev)
--
1.9.1



2018-07-06 04:07:15

by Vinod Koul

[permalink] [raw]
Subject: Re: [PATCH 1/1] remoteproc: correct rproc_free_vring() to avoid invalid kernel paging

On 05-07-18, 17:59, Loic Pallardy wrote:
> If rproc_start() failed, rproc_resource_cleanup() is called to clean
> debufs entries, then associated iommu mappings, carveouts and vdev.

typo debufs...

> Issue occurs when rproc_free_vring() is trying to reset vring resource
> table entry.
> At this time, table_ptr is pointing on loaded resource table and carveouts
> amready released, so access to loaded resource table is generating a kernel

typo amready..

> paging error:
>
> [ 12.696535] Unable to handle kernel paging request at virtual address f0f357cc
> [ 12.696540] pgd = (ptrval)
> [ 12.696542] [f0f357cc] *pgd=6d2d0811, *pte=00000000, *ppte=00000000
> [ 12.696558] Internal error: Oops: 807 [#1] SMP ARM
> [ 12.696563] Modules linked in: rpmsg_core v4l2_mem2mem videobuf2_dma_contig sti_drm v4l2_common vida
> [ 12.696598] CPU: 1 PID: 48 Comm: kworker/1:1 Tainted: G W 4.18.0-rc2-00018-g3170fdd-8
> [ 12.696602] Hardware name: STi SoC with Flattened Device Tree
> [ 12.696625] Workqueue: events request_firmware_work_func
> [ 12.696659] PC is at rproc_free_vring+0x84/0xbc [remoteproc]
> [ 12.696667] LR is at rproc_free_vring+0x70/0xbc [remoteproc]
>
> This patch proposes to simply remove reset of resource table vring entries,
> as firmware and resource table are reloaded at each rproc boot.
> rproc_trigger_recovery() not impacted as resources not touched during recovery
> procedure.
>
> Signed-off-by: Loic Pallardy <[email protected]>
> ---
> drivers/remoteproc/remoteproc_core.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index a9609d9..9a8b47c 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -289,16 +289,10 @@ void rproc_free_vring(struct rproc_vring *rvring)
> {
> int size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
> struct rproc *rproc = rvring->rvdev->rproc;
> - int idx = rvring->rvdev->vring - rvring;
> - struct fw_rsc_vdev *rsc;
>
> dma_free_coherent(rproc->dev.parent, size, rvring->va, rvring->dma);
> idr_remove(&rproc->notifyids, rvring->notifyid);
>
> - /* reset resource entry info */
> - rsc = (void *)rproc->table_ptr + rvring->rvdev->rsc_offset;
> - rsc->vring[idx].da = 0;
> - rsc->vring[idx].notifyid = -1;
> }
>
> static int rproc_vdev_do_probe(struct rproc_subdev *subdev)
> --
> 1.9.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-remoteproc" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--
~Vinod