Felipe,
On Mon, Dec 20, 2010 at 11:12 AM, Felipe Contreras
<felipe.contreras@xxxxxxxxx> wrote:
> We need to protect not only the dmm_map list, but the individual
> map_obj's, otherwise, we might be building the scatter-gather list with
> garbage. So, use the existing proc_lock for that.
>
> I observed race conditions which caused kernel panics while running
> stress tests. This patch fixes those.
>
> Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx>
> ---
> drivers/staging/tidspbridge/rmgr/proc.c | 18 ++++++++++++++----
> 1 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/tidspbridge/rmgr/proc.c b/drivers/staging/tidspbridge/rmgr/proc.c
> index b47d7aa..21052e3 100644
> --- a/drivers/staging/tidspbridge/rmgr/proc.c
> +++ b/drivers/staging/tidspbridge/rmgr/proc.c
> @@ -781,12 +781,14 @@ int proc_begin_dma(void *hprocessor, void *pmpu_addr, u32 ul_size,
> (u32)pmpu_addr,
> ul_size, dir);
>
> + mutex_lock(&proc_lock);
May be you should use mutex_lock_interruptable instead of mutex_lock.
> +
> /* find requested memory are in cached mapping information */
> map_obj = find_containing_mapping(pr_ctxt, (u32) pmpu_addr, ul_size);
> if (!map_obj) {
> pr_err("%s: find_containing_mapping failed\n", __func__);
> status = -EFAULT;
> - goto err_out;
> + goto no_map;
> }
>
> if (memory_give_ownership(map_obj, (u32) pmpu_addr, ul_size, dir)) {
> @@ -795,6 +797,8 @@ int proc_begin_dma(void *hprocessor, void *pmpu_addr, u32 ul_size,
> status = -EFAULT;
> }
>
> +no_map:
> + mutex_unlock(&proc_lock);
> err_out:
>
> return status;
> @@ -819,12 +823,14 @@ int proc_end_dma(void *hprocessor, void *pmpu_addr, u32 ul_size,
> (u32)pmpu_addr,
> ul_size, dir);
>
> + mutex_lock(&proc_lock);
> +
> /* find requested memory are in cached mapping information */
> map_obj = find_containing_mapping(pr_ctxt, (u32) pmpu_addr, ul_size);
> if (!map_obj) {
> pr_err("%s: find_containing_mapping failed\n", __func__);
> status = -EFAULT;
> - goto err_out;
> + goto no_map;
> }
>
> if (memory_regain_ownership(map_obj, (u32) pmpu_addr, ul_size, dir)) {
> @@ -834,6 +840,8 @@ int proc_end_dma(void *hprocessor, void *pmpu_addr, u32 ul_size,
> goto err_out;
Mutex is not released in this case as it is released only at no_map.
> }
>
> +no_map:
> + mutex_unlock(&proc_lock);
> err_out:
> return status;
> }
> @@ -1726,9 +1734,8 @@ int proc_un_map(void *hprocessor, void *map_addr,
> (p_proc_object->hbridge_context, va_align, size_align);
> }
>
> - mutex_unlock(&proc_lock);
> if (status)
> - goto func_end;
> + goto unmap_failed;
>
> /*
> * A successful unmap should be followed by removal of map_obj
> @@ -1737,6 +1744,9 @@ int proc_un_map(void *hprocessor, void *map_addr,
> */
> remove_mapping_information(pr_ctxt, (u32) map_addr, size_align);
>
> +unmap_failed:
> + mutex_unlock(&proc_lock);
> +
> func_end:
> dev_dbg(bridge, "%s: hprocessor: 0x%p map_addr: 0x%p status: 0x%x\n",
> __func__, hprocessor, map_addr, status);
> --
> 1.7.3.3
>
> --
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--
Thank you,
Best regards,
Hari Kanigeri
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