4.9-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 546c0547555efca8ba8c120716c325435e29df1b ]
When dma_cookie_complete() is called in hidma_process_completed(), dma_cookie_status() will return DMA_COMPLETE in hidma_tx_status(). Then, hidma_txn_is_success() will be called to use channel cookie mchan->last_success to do additional DMA status check. Current code assigns mchan->last_success after dma_cookie_complete(). This causes a race condition of dma_cookie_status() returns DMA_COMPLETE before mchan->last_success is assigned correctly. The race will cause hidma_tx_status() return DMA_ERROR but the transaction is actually a success. Moreover, in async_tx case, it will cause a timeout panic in async_tx_quiesce().
Kernel panic - not syncing: async_tx_quiesce: DMA error waiting for transaction ... Call trace: [<ffff000008089994>] dump_backtrace+0x0/0x1f4 [<ffff000008089bac>] show_stack+0x24/0x2c [<ffff00000891e198>] dump_stack+0x84/0xa8 [<ffff0000080da544>] panic+0x12c/0x29c [<ffff0000045d0334>] async_tx_quiesce+0xa4/0xc8 [async_tx] [<ffff0000045d03c8>] async_trigger_callback+0x70/0x1c0 [async_tx] [<ffff0000048b7d74>] raid_run_ops+0x86c/0x1540 [raid456] [<ffff0000048bd084>] handle_stripe+0x5e8/0x1c7c [raid456] [<ffff0000048be9ec>] handle_active_stripes.isra.45+0x2d4/0x550 [raid456] [<ffff0000048beff4>] raid5d+0x38c/0x5d0 [raid456] [<ffff000008736538>] md_thread+0x108/0x168 [<ffff0000080fb1cc>] kthread+0x10c/0x138 [<ffff000008084d34>] ret_from_fork+0x10/0x18
Cc: Joey Zheng yu.zheng@hxt-semitech.com Reviewed-by: Sinan Kaya okaya@kernel.org Signed-off-by: Shunyong Yang shunyong.yang@hxt-semitech.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/qcom/hidma.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c index e244e10a94b5..5444f39bf939 100644 --- a/drivers/dma/qcom/hidma.c +++ b/drivers/dma/qcom/hidma.c @@ -131,24 +131,25 @@ static void hidma_process_completed(struct hidma_chan *mchan) desc = &mdesc->desc; last_cookie = desc->cookie;
+ llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch); + spin_lock_irqsave(&mchan->lock, irqflags); + if (llstat == DMA_COMPLETE) { + mchan->last_success = last_cookie; + result.result = DMA_TRANS_NOERROR; + } else { + result.result = DMA_TRANS_ABORTED; + } + dma_cookie_complete(desc); spin_unlock_irqrestore(&mchan->lock, irqflags);
- llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch); dmaengine_desc_get_callback(desc, &cb);
dma_run_dependencies(desc);
spin_lock_irqsave(&mchan->lock, irqflags); list_move(&mdesc->node, &mchan->free); - - if (llstat == DMA_COMPLETE) { - mchan->last_success = last_cookie; - result.result = DMA_TRANS_NOERROR; - } else - result.result = DMA_TRANS_ABORTED; - spin_unlock_irqrestore(&mchan->lock, irqflags);
dmaengine_desc_callback_invoke(&cb, &result);