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Subject[PATCH AUTOSEL 5.4 16/58] HID: hid-bigbenff: fix race condition for scheduled work during removal
Date
From: Hanno Zulla <kontakt@hanno.de>

[ Upstream commit 4eb1b01de5b9d8596d6c103efcf1a15cfc1bedf7 ]

It's possible that there is scheduled work left while the device is
already being removed, which can cause a kernel crash. Adding a flag
will avoid this.

Signed-off-by: Hanno Zulla <kontakt@hanno.de>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-bigbenff.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index f8c552b64a899..db6da21ade063 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -174,6 +174,7 @@ static __u8 pid0902_rdesc_fixed[] = {
struct bigben_device {
struct hid_device *hid;
struct hid_report *report;
+ bool removed;
u8 led_state; /* LED1 = 1 .. LED4 = 8 */
u8 right_motor_on; /* right motor off/on 0/1 */
u8 left_motor_force; /* left motor force 0-255 */
@@ -190,6 +191,9 @@ static void bigben_worker(struct work_struct *work)
struct bigben_device, worker);
struct hid_field *report_field = bigben->report->field[0];

+ if (bigben->removed)
+ return;
+
if (bigben->work_led) {
bigben->work_led = false;
report_field->value[0] = 0x01; /* 1 = led message */
@@ -304,6 +308,7 @@ static void bigben_remove(struct hid_device *hid)
{
struct bigben_device *bigben = hid_get_drvdata(hid);

+ bigben->removed = true;
cancel_work_sync(&bigben->worker);
hid_hw_stop(hid);
}
@@ -324,6 +329,7 @@ static int bigben_probe(struct hid_device *hid,
return -ENOMEM;
hid_set_drvdata(hid, bigben);
bigben->hid = hid;
+ bigben->removed = false;

error = hid_parse(hid);
if (error) {
--
2.20.1
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