mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-01 06:33:07 +00:00
drivers: tty: serial: Fix deadlock in sa1100_set_termios()
[ Upstream commit 62b2caef40
]
There is a deadlock in sa1100_set_termios(), which is shown
below:
(Thread 1) | (Thread 2)
| sa1100_enable_ms()
sa1100_set_termios() | mod_timer()
spin_lock_irqsave() //(1) | (wait a time)
... | sa1100_timeout()
del_timer_sync() | spin_lock_irqsave() //(2)
(wait timer to stop) | ...
We hold sport->port.lock in position (1) of thread 1 and
use del_timer_sync() to wait timer to stop, but timer handler
also need sport->port.lock in position (2) of thread 2. As a result,
sa1100_set_termios() will block forever.
This patch moves del_timer_sync() before spin_lock_irqsave()
in order to prevent the deadlock.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20220417111626.7802-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
aca0cab0e9
commit
553213432e
1 changed files with 2 additions and 2 deletions
|
@ -446,6 +446,8 @@ sa1100_set_termios(struct uart_port *port, struct ktermios *termios,
|
|||
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
|
||||
quot = uart_get_divisor(port, baud);
|
||||
|
||||
del_timer_sync(&sport->timer);
|
||||
|
||||
spin_lock_irqsave(&sport->port.lock, flags);
|
||||
|
||||
sport->port.read_status_mask &= UTSR0_TO_SM(UTSR0_TFS);
|
||||
|
@ -476,8 +478,6 @@ sa1100_set_termios(struct uart_port *port, struct ktermios *termios,
|
|||
UTSR1_TO_SM(UTSR1_ROR);
|
||||
}
|
||||
|
||||
del_timer_sync(&sport->timer);
|
||||
|
||||
/*
|
||||
* Update the per-port timeout.
|
||||
*/
|
||||
|
|
Loading…
Reference in a new issue