>-----Original Message----- >From: dri-devel <dri-devel-boun...@lists.freedesktop.org> On Behalf Of >guangming....@mediatek.com >Sent: Thursday, January 13, 2022 7:34 AM >To: sumit.sem...@linaro.org >Cc: linux-arm-ker...@lists.infradead.org; mingyuan...@mediatek.com; >Guangming <guangming....@mediatek.com>; >wsd_upstr...@mediatek.com; linux-ker...@vger.kernel.org; dri- >de...@lists.freedesktop.org; linaro-mm-...@lists.linaro.org; >yf.w...@mediatek.com; libo.k...@mediatek.com; >benjamin.gaign...@linaro.org; bo.s...@mediatek.com; >matthias....@gmail.com; linux-media...@lists.infradead.org; >lm...@codeaurora.org; labb...@redhat.com; christian.koe...@amd.com; >jianjiao.z...@mediatek.com; linux-me...@vger.kernel.org >Subject: [PATCH v3] dma-buf: dma-heap: Add a size check for allocation > >From: Guangming <guangming....@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....@mediatek.com> >Signed-off-by: jianjiao zeng <jianjiao.z...@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 >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. >+ */ >+ if (len >> PAGE_SHIFT > totalram_pages())
If your "heap" is from cma, is this still a valid check? M >+ return -EINVAL; > /* > * Allocations from all heaps have to begin > * and end on page boundaries. >-- >2.17.1
