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Subject[PATCH] ath9k: fix possible sleep-in-atomic-context bugs in hif_usb_send_regout()
Date
The driver may sleep while holding a spinlock.
The function call path (from bottom to top) in Linux 4.19 is:

drivers/net/wireless/ath/ath9k/hif_usb.c, 108:
usb_alloc_urb(GFP_KERNEL) in hif_usb_send_regout
drivers/net/wireless/ath/ath9k/hif_usb.c, 470:
hif_usb_send_regout in hif_usb_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 34:
(FUNC_PTR)hif_usb_send in htc_issue_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 295:
htc_issue_send in htc_send
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 250:
htc_send in ath9k_htc_send_beacon
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 207:
spin_lock_bh in ath9k_htc_send_beacon

drivers/net/wireless/ath/ath9k/hif_usb.c, 112:
kzalloc(GFP_KERNEL) in hif_usb_send_regout
drivers/net/wireless/ath/ath9k/hif_usb.c, 470:
hif_usb_send_regout in hif_usb_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 34:
(FUNC_PTR)hif_usb_send in htc_issue_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 295:
htc_issue_send in htc_send
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 250:
htc_send in ath9k_htc_send_beacon
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 207:
spin_lock_bh in ath9k_htc_send_beacon

drivers/net/wireless/ath/ath9k/hif_usb.c, 127:
usb_submit_urb(GFP_KERNEL) in hif_usb_send_regout
drivers/net/wireless/ath/ath9k/hif_usb.c, 470:
hif_usb_send_regout in hif_usb_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 34:
(FUNC_PTR)hif_usb_send in htc_issue_send
drivers/net/wireless/ath/ath9k/htc_hst.c, 295:
htc_issue_send in htc_send
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 250:
htc_send in ath9k_htc_send_beacon
drivers/net/wireless/ath/ath9k/htc_drv_beacon.c, 207:
spin_lock_bh in ath9k_htc_send_beacon

(FUNC_PTR) means a function pointer is called.

To fix these bugs, GFP_KERNEL is replaced with GFP_ATOMIC.

These bugs are found by a static analysis tool STCheck written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/net/wireless/ath/ath9k/hif_usb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index fb649d85b8fc..37231fde102d 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -105,11 +105,11 @@ static int hif_usb_send_regout(struct hif_device_usb *hif_dev,
struct cmd_buf *cmd;
int ret = 0;

- urb = usb_alloc_urb(0, GFP_KERNEL);
+ urb = usb_alloc_urb(0, GFP_ATOMIC);
if (urb == NULL)
return -ENOMEM;

- cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
+ cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
if (cmd == NULL) {
usb_free_urb(urb);
return -ENOMEM;
@@ -124,7 +124,7 @@ static int hif_usb_send_regout(struct hif_device_usb *hif_dev,
hif_usb_regout_cb, cmd, 1);

usb_anchor_urb(urb, &hif_dev->regout_submitted);
- ret = usb_submit_urb(urb, GFP_KERNEL);
+ ret = usb_submit_urb(urb, GFP_ATOMIC);
if (ret) {
usb_unanchor_urb(urb);
kfree(cmd);
--
2.17.1
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