Duoming Zhou 01f1ae2733 dmaengine: mediatek: Fix deadlock caused by synchronize_irq() ... 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>		2023-10-04 19:26:36 +05:30
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Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile	dmaengine updates for v5.3-rc1	2019-07-17 09:55:43 -07:00
mtk-cqdma.c	dmaengine: Explicitly include correct DT includes	2023-08-01 23:51:27 +05:30
mtk-hsdma.c	dmaengine: Explicitly include correct DT includes	2023-08-01 23:51:27 +05:30
mtk-uart-apdma.c	dmaengine: mediatek: Fix deadlock caused by synchronize_irq()	2023-10-04 19:26:36 +05:30