diff options
| author | Ilpo Järvinen | 2023-01-30 13:48:40 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2023-02-09 11:28:25 +0100 |
| commit | bd8d2ba9d9e0afd987764fd94a532b683a793d00 (patch) | |
| tree | b3a5c62305d9fd3cf3d7e17584003457c91a7f20 /drivers/tty | |
| parent | 5f3dedbc3bf483377d39ef2e83ecf1f8723dc220 (diff) | |
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')
| -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 b85c82616e8c..cc521f6232fd 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -57,6 +57,18 @@ 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); |