From: Roderick Colenbrander Date: Fri, 2 Aug 2019 22:50:19 +0000 (-0700) Subject: HID: sony: Fix race condition between rumble and device remove. X-Git-Tag: Ubuntu-4.15.0-65.74~193 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=86938d248622391c3c8d559e998ca12f7a60cac9;p=mirror_ubuntu-bionic-kernel.git HID: sony: Fix race condition between rumble and device remove. BugLink: https://bugs.launchpad.net/bugs/1840520 commit e0f6974a54d3f7f1b5fdf5a593bd43ce9206ec04 upstream. 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 CC: stable@vger.kernel.org Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Kleber Sacilotto de Souza --- diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c index b9dc3ac4d4aa..15173cd29eb8 100644 --- a/drivers/hid/hid-sony.c +++ b/drivers/hid/hid-sony.c @@ -578,10 +578,14 @@ 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) @@ -2494,13 +2498,18 @@ 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) {