[PATCH 3.18 16/50] isdn: Fix a sleep-in-atomic bug

From: Greg Kroah-Hartman
Date: Fri Aug 04 2017 - 19:29:44 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jia-Ju Bai <baijiaju1990@xxxxxxx>

commit e8f4ae85439f34bec3b0ab69223a41809dab28c9 upstream.

The driver may sleep under a spin lock, the function call path is:
isdn_ppp_mp_receive (acquire the lock)
isdn_ppp_mp_reassembly
isdn_ppp_push_higher
isdn_ppp_decompress
isdn_ppp_ccp_reset_trans
isdn_ppp_ccp_reset_alloc_state
kzalloc(GFP_KERNEL) --> may sleep

To fixed it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/isdn/i4l/isdn_ppp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -2364,7 +2364,7 @@ static struct ippp_ccp_reset_state *isdn
id);
return NULL;
} else {
- rs = kzalloc(sizeof(struct ippp_ccp_reset_state), GFP_KERNEL);
+ rs = kzalloc(sizeof(struct ippp_ccp_reset_state), GFP_ATOMIC);
if (!rs)
return NULL;
rs->state = CCPResetIdle;