diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2023-01-30 14:48:40 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-02-22 14:46:03 +0300 |
| commit | 8e665906011cb048afdc656a8e62caab21215bab (patch) | |
| tree | 6f6dbdc77adf5c54f51c481f98e4f97c1fed5c82 /drivers/tty/serial | |
| parent | 7fe583c9bec10cd4b76231c51b37f3e4ca646e01 (diff) | |
| download | linux-8e665906011cb048afdc656a8e62caab21215bab.tar.xz | |
serial: 8250_dma: Fix DMA Rx completion race
commit 31352811e13dc2313f101b890fd4b1ce760b5fe7 upstream.
__dma_rx_complete() is called from two places:
- Through the DMA completion callback dma_rx_complete()
- From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT
The former does not hold port's lock during __dma_rx_complete() which
allows these two to race and potentially insert the same data twice.
Extend port's lock coverage in dma_rx_complete() to prevent the race
and check if the DMA Rx is still pending completion before calling
into __dma_rx_complete().
Reported-by: Gilles BULOZ <gilles.buloz@kontron.com>
Tested-by: Gilles BULOZ <gilles.buloz@kontron.com>
Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial')
| -rw-r--r-- | drivers/tty/serial/8250/8250_dma.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 26f17456b0d7..380b76f6dbc7 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -65,6 +65,18 @@ static void __dma_rx_complete(void *param) tty_flip_buffer_push(tty_port); } +static void dma_rx_complete(void *param) +{ + struct uart_8250_port *p = param; + struct uart_8250_dma *dma = p->dma; + unsigned long flags; + + spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + spin_unlock_irqrestore(&p->port.lock, flags); +} + int serial8250_tx_dma(struct uart_8250_port *p) { struct uart_8250_dma *dma = p->dma; @@ -130,7 +142,7 @@ int serial8250_rx_dma(struct uart_8250_port *p) return -EBUSY; dma->rx_running = 1; - desc->callback = __dma_rx_complete; + desc->callback = dma_rx_complete; desc->callback_param = p; dma->rx_cookie = dmaengine_submit(desc); |