This is a note to let you know that I've just added the patch titled dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources to the 5.17-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dmaengine-mediatek-fix-pm-usage-reference-leak-of-mt.patch and it can be found in the queue-5.17 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6ca6755530ef99348f31bd3571a39e670793ca1e Author: zhangqilong <zhangqilong3@xxxxxxxxxx> Date: Sat Mar 19 10:21:42 2022 +0800 dmaengine: mediatek:Fix PM usage reference leak of mtk_uart_apdma_alloc_chan_resources [ Upstream commit 545b2baac89b859180e51215468c05d85ea8465a ] pm_runtime_get_sync will increment pm usage counter even it failed. Forgetting to putting operation will result in reference leak here. We fix it: 1) Replacing it with pm_runtime_resume_and_get to keep usage counter balanced. 2) Add putting operation before returning error. Fixes:9135408c3ace4 ("dmaengine: mediatek: Add MediaTek UART APDMA support") Signed-off-by: Zhang Qilong <zhangqilong3@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220319022142.142709-1-zhangqilong3@xxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c index 375e7e647df6..a1517ef1f4a0 100644 --- a/drivers/dma/mediatek/mtk-uart-apdma.c +++ b/drivers/dma/mediatek/mtk-uart-apdma.c @@ -274,7 +274,7 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan) unsigned int status; int ret; - ret = pm_runtime_get_sync(mtkd->ddev.dev); + ret = pm_runtime_resume_and_get(mtkd->ddev.dev); if (ret < 0) { pm_runtime_put_noidle(chan->device->dev); return ret; @@ -288,18 +288,21 @@ static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan) ret = readx_poll_timeout(readl, c->base + VFF_EN, status, !status, 10, 100); if (ret) - return ret; + goto err_pm; ret = request_irq(c->irq, mtk_uart_apdma_irq_handler, IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan); if (ret < 0) { dev_err(chan->device->dev, "Can't request dma IRQ\n"); - return -EINVAL; + ret = -EINVAL; + goto err_pm; } if (mtkd->support_33bits) mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B); +err_pm: + pm_runtime_put_noidle(mtkd->ddev.dev); return ret; }