serial8250_em485_init() is supposed to be protected with
p->port.lock spinlock.
This may lead to issues when kmalloc sleeps, so it is better to use
GFP_ATOMIC in this spinlocked context.

Fixes: e490c9144cfa ("tty: Add software emulated RS485 support for 8250")
Reported-by: Ильяс Гасанов <torso.n...@gmail.com>
Signed-off-by: Matwey V. Kornilov <mat...@sai.msu.ru>
---
Changes from v1:
 - Properly filled Reported-by: tag

 drivers/tty/serial/8250/8250_port.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c 
b/drivers/tty/serial/8250/8250_port.c
index c908b77..4d6deef 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -586,7 +586,7 @@ int serial8250_em485_init(struct uart_8250_port *p)
        if (p->em485 != NULL)
                return 0;
 
-       p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_KERNEL);
+       p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
        if (p->em485 == NULL)
                return -ENOMEM;
 
-- 
2.7.0

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