[PATCH 5.19 043/155] ethernet: rocker: fix sleep in atomic context bug in neigh_timer_handler

Greg Kroah-Hartman
2022-09-06T14:02:57Z

From: Duoming Zhou <duoming@zju.edu.cn>

[ Upstream commit c0955bf957be4bead01fae1d791476260da7325d ]

The function neigh_timer_handler() is a timer handler that runs in an
atomic context. When used by rocker, neigh_timer_handler() calls
"kzalloc(.., GFP_KERNEL)" that may sleep. As a result, the sleep in
atomic context bug will happen. One of the processes is shown below:

ofdpa_fib4_add()
...
neigh_add_timer()

(wait a timer)

neigh_timer_handler()
neigh_release()
neigh_destroy()
rocker_port_neigh_destroy()
rocker_world_port_neigh_destroy()
ofdpa_port_neigh_destroy()
ofdpa_port_ipv4_neigh()
kzalloc(sizeof(.., GFP_KERNEL) //may sleep

This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to
GFP_ATOMIC in order to mitigate the bug.

Fixes: 00fc0c51e35b ("rocker: Change world_ops API and implementation to be switchdev independant")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/rocker/rocker_ofdpa.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/rocker/rocker_ofdpa.c b/drivers/net/ethernet/rocker/rocker_ofdpa.c
index bc70c6abd6a5b..58cf7cc54f408 100644
--- a/drivers/net/ethernet/rocker/rocker_ofdpa.c
+++ b/drivers/net/ethernet/rocker/rocker_ofdpa.c
@@ -1273,7 +1273,7 @@ static int ofdpa_port_ipv4_neigh(struct ofdpa_port *ofdpa_port,
bool removing;
int err = 0;

- entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
if (!entry)
return -ENOMEM;

--
2.35.1