Duoming Zhou 4da05eba66 dmaengine: mediatek: Fix deadlock caused by synchronize_irq() ... [ Upstream commit 01f1ae2733 ] The synchronize_irq(c->irq) will not return until the IRQ handler mtk_uart_apdma_irq_handler() is completed. If the synchronize_irq() holds a spin_lock and waits the IRQ handler to complete, but the IRQ handler also needs the same spin_lock. The deadlock will happen. The process is shown below: cpu0 cpu1 mtk_uart_apdma_device_pause() | mtk_uart_apdma_irq_handler() spin_lock_irqsave() | | spin_lock_irqsave() //hold the lock to wait | synchronize_irq() | This patch reorders the synchronize_irq(c->irq) outside the spin_lock in order to mitigate the bug. Fixes: 9135408c3a ("dmaengine: mediatek: Add MediaTek UART APDMA support") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Reviewed-by: Eugen Hristev <eugen.hristev@collabora.com> Link: https://lore.kernel.org/r/20230806032511.45263-1-duoming@zju.edu.cn Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-10-19 23:05:37 +02:00
..
Kconfig
Makefile
mtk-cqdma.c
mtk-hsdma.c	dmaengine: mediatek: mtk-hsdma: Fix a resource leak in the error handling path of the probe function	2020-12-29 10:07:59 +05:30
mtk-uart-apdma.c	dmaengine: mediatek: Fix deadlock caused by synchronize_irq()	2023-10-19 23:05:37 +02:00