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authorDuoming Zhou2023-08-06 11:25:11 +0800
committerGreg Kroah-Hartman2023-10-19 23:08:58 +0200
commit9a995e11b23f4afb4fe50e7d4d420e3ddcaa35a1 (patch)
tree7628fef2858409df0873047cd43dfaeba61a06bf /samples/kdb
parent01b19fc6621d2b10d2433b1f0259f5745e403cd9 (diff)
dmaengine: mediatek: Fix deadlock caused by synchronize_irq()
[ Upstream commit 01f1ae2733e2bb4de92fefcea5fda847d92aede1 ] 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: 9135408c3ace ("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>
Diffstat (limited to 'samples/kdb')
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