-
Alexander Sverdlin authored
From time to time DMA completion can come in the middle of DMA shutdown: <process ctx>: <IRQ>: lpuart32_shutdown() lpuart_dma_shutdown() del_timer_sync() lpuart_dma_rx_complete() lpuart_copy_rx_to_tty() mod_timer() lpuart_dma_rx_free() When the timer fires a bit later, sport->dma_rx_desc is NULL: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 pc : lpuart_copy_rx_to_tty+0xcc/0x5bc lr : lpuart_timer_func+0x1c/0x2c Call trace: lpuart_copy_rx_to_tty lpuart_timer_func call_timer_fn __run_timers.part.0 run_timer_softirq __do_softirq __irq_exit_rcu irq_exit handle_domain_irq gic_handle_irq call_on_irq_stack do_interrupt_handler ... To fix this fold del_timer_sync() into lpuart_dma_rx_free() after dmaengine_terminate_sync() to make sure timer will not be re-started in lpuart_copy_rx_to_tty() <= lpuart_dma_rx_complete(). Fixes: 4a8588a1 ("serial: fsl_lpuart: delete timer on shutdown") Cc: stable <stable@kernel.org> Signed-off-by:
Alexander Sverdlin <alexander.sverdlin@siemens.com> Link: https://lore.kernel.org/r/20230309134302.74940-2-alexander.sverdlin@siemens.comSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1be6f2b1