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| author | Andrew Liu <shengping.liu@windriver.com> | 2008-04-29 17:36:25 +1000 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2008-05-01 11:59:12 -0600 |
| commit | fbe543b412cef02350fab35526a6d4dc3d20d182 (patch) | |
| tree | a47e56379bc0611e1d15e6318c58d9a3bcd23478 /drivers/serial/mpc52xx_uart.c | |
| parent | 80791be11145f7dd7f68c84741fc66e5164b7353 (diff) | |
| download | lwn-fbe543b412cef02350fab35526a6d4dc3d20d182.tar.gz lwn-fbe543b412cef02350fab35526a6d4dc3d20d182.zip | |
Fix a potential issue in mpc52xx uart driver
mpc52xx_uart_int and __uart_put_char both try to acquire the
port->lock. Therefore the function sequence of:
mpc52xx_uart_int--> ...-->flush_to_ldisc-->...-->__uart_put_char
can potentially trigger a deadlock. To avoid this deadlock a fix
similar to that found in the 8250.c serial driver is applied. The
deadlock is avoided by releasing the lock before pushing a buffer
and reacquiring it when completed.
Signed-off-by: Andrew Liu <shengping.liu@windriver.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/serial/mpc52xx_uart.c')
| -rw-r--r-- | drivers/serial/mpc52xx_uart.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c index 7a3625f52a03..efc971d9647b 100644 --- a/drivers/serial/mpc52xx_uart.c +++ b/drivers/serial/mpc52xx_uart.c @@ -783,7 +783,9 @@ mpc52xx_uart_int_rx_chars(struct uart_port *port) } } + spin_unlock(&port->lock); tty_flip_buffer_push(tty); + spin_lock(&port->lock); return psc_ops->raw_rx_rdy(port); } |