-----Original Message----- From: dri-devel dri-devel-bounces@lists.freedesktop.org On Behalf Of Ruhl, Michael J Sent: Thursday, January 13, 2022 7:58 AM To: guangming.cao@mediatek.com; sumit.semwal@linaro.org Cc: jianjiao.zeng@mediatek.com; lmark@codeaurora.org; wsd_upstream@mediatek.com; christian.koenig@amd.com; linux- kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; yf.wang@mediatek.com; linaro-mm-sig@lists.linaro.org; linux- mediatek@lists.infradead.org; libo.kang@mediatek.com; benjamin.gaignard@linaro.org; bo.song@mediatek.com; matthias.bgg@gmail.com; labbott@redhat.com; mingyuan.ma@mediatek.com; linux-arm-kernel@lists.infradead.org; linux- media@vger.kernel.org Subject: RE: [PATCH v3] dma-buf: dma-heap: Add a size check for allocation
-----Original Message----- From: dri-devel dri-devel-bounces@lists.freedesktop.org On Behalf Of guangming.cao@mediatek.com Sent: Thursday, January 13, 2022 7:34 AM To: sumit.semwal@linaro.org Cc: linux-arm-kernel@lists.infradead.org; mingyuan.ma@mediatek.com; Guangming Guangming.Cao@mediatek.com; wsd_upstream@mediatek.com; linux-kernel@vger.kernel.org; dri- devel@lists.freedesktop.org; linaro-mm-sig@lists.linaro.org; yf.wang@mediatek.com; libo.kang@mediatek.com; benjamin.gaignard@linaro.org; bo.song@mediatek.com; matthias.bgg@gmail.com; linux-mediatek@lists.infradead.org; lmark@codeaurora.org; labbott@redhat.com; christian.koenig@amd.com; jianjiao.zeng@mediatek.com; linux-media@vger.kernel.org Subject: [PATCH v3] dma-buf: dma-heap: Add a size check for allocation
From: Guangming Guangming.Cao@mediatek.com
Add a size check for allocation since the allocation size is always less than the total DRAM size.
Without this check, once the invalid size allocation runs on a process that can't be killed by OOM flow(such as "gralloc" on Android devices), it will cause a kernel exception, and to make matters worse, we can't find who are using so many memory with "dma_buf_debug_show" since the relevant dma-buf hasn't exported.
To make OOM issue easier, maybe need dma-buf framework to dump the buffer size under allocating in "dma_buf_debug_show".
Signed-off-by: Guangming Guangming.Cao@mediatek.com Signed-off-by: jianjiao zeng jianjiao.zeng@mediatek.com
v3: 1. update patch, use right shift to replace division. 2. update patch, add reason in code and commit message. v2: 1. update size limitation as total_dram page size. 2. update commit message
drivers/dma-buf/dma-heap.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 56bf5ad01ad5..1fd382712584 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -55,6 +55,16 @@ static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len, struct dma_buf *dmabuf; int fd;
- /*
* Invalid size check. The "len" should be less than totalram.** Without this check, once the invalid size allocation runs on a processthat
* can't be killed by OOM flow(such as "gralloc" on Android devices), itwill
* cause a kernel exception, and to make matters worse, we can't findwho are using
* so many memory with "dma_buf_debug_show" since the relevantdma-buf hasn't exported.
*/- if (len >> PAGE_SHIFT > totalram_pages())
If your "heap" is from cma, is this still a valid check?
And thinking a bit further, if I create a heap from something else (say device memory), you will need to be able to figure out the maximum allowable check for the specific heap.
Maybe the heap needs a callback for max size?
m
M
return -EINVAL;
- Allocations from all heaps have to begin
- and end on page boundaries.
-- 2.17.1