diff options
| author | Roderick Colenbrander <roderick@gaikai.com> | 2019-08-02 15:50:19 -0700 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2019-08-06 12:46:15 +0200 |
| commit | e0f6974a54d3f7f1b5fdf5a593bd43ce9206ec04 (patch) | |
| tree | 2e217dec39f7f52d1cbfb53f883c683ce740f47c /drivers/hid | |
| parent | 6d4472d7bec39917b54e4e80245784ea5d60ce49 (diff) | |
HID: sony: Fix race condition between rumble and device remove.
Valve reported a kernel crash on Ubuntu 18.04 when disconnecting a DS4
gamepad while rumble is enabled. This issue is reproducible with a
frequency of 1 in 3 times in the game Borderlands 2 when using an
automatic weapon, which triggers many rumble operations.
We found the issue to be a race condition between sony_remove and the
final device destruction by the HID / input system. The problem was
that sony_remove didn't clean some of its work_item state in
"struct sony_sc". After sony_remove work, the corresponding evdev
node was around for sufficient time for applications to still queue
rumble work after "sony_remove".
On pre-4.19 kernels the race condition caused a kernel crash due to a
NULL-pointer dereference as "sc->output_report_dmabuf" got freed during
sony_remove. On newer kernels this crash doesn't happen due the buffer
now being allocated using devm_kzalloc. However we can still queue work,
while the driver is an undefined state.
This patch fixes the described problem, by guarding the work_item
"state_worker" with an initialized variable, which we are setting back
to 0 on cleanup.
Signed-off-by: Roderick Colenbrander <roderick.colenbrander@sony.com>
CC: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid')
| -rw-r--r-- | drivers/hid/hid-sony.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c index 93942063b51b..49dd2d905c7f 100644 --- a/drivers/hid/hid-sony.c +++ b/drivers/hid/hid-sony.c @@ -585,10 +585,14 @@ static void sony_set_leds(struct sony_sc *sc); static inline void sony_schedule_work(struct sony_sc *sc, enum sony_worker which) { + unsigned long flags; + switch (which) { case SONY_WORKER_STATE: - if (!sc->defer_initialization) + spin_lock_irqsave(&sc->lock, flags); + if (!sc->defer_initialization && sc->state_worker_initialized) schedule_work(&sc->state_worker); + spin_unlock_irqrestore(&sc->lock, flags); break; case SONY_WORKER_HOTPLUG: if (sc->hotplug_worker_initialized) @@ -2558,13 +2562,18 @@ static inline void sony_init_output_report(struct sony_sc *sc, static inline void sony_cancel_work_sync(struct sony_sc *sc) { + unsigned long flags; + if (sc->hotplug_worker_initialized) cancel_work_sync(&sc->hotplug_worker); - if (sc->state_worker_initialized) + if (sc->state_worker_initialized) { + spin_lock_irqsave(&sc->lock, flags); + sc->state_worker_initialized = 0; + spin_unlock_irqrestore(&sc->lock, flags); cancel_work_sync(&sc->state_worker); + } } - static int sony_input_configured(struct hid_device *hdev, struct hid_input *hidinput) { |