From: Dongliang Mu mudongliangabcd@gmail.com
stable inclusion from linux-4.19.207 commit fba6d1d3645cf45f17c60faeb419dd3cc3fdd6e8
--------------------------------
[ Upstream commit 6fa54bc713c262e1cfbc5613377ef52280d7311f ]
If em28xx_ir_init fails, it would decrease the refcount of dev. However, in the em28xx_ir_fini, when ir is NULL, it goes to ref_put and decrease the refcount of dev. This will lead to a refcount bug.
Fix this bug by removing the kref_put in the error handling code of em28xx_ir_init.
refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x18e/0x1a0 lib/refcount.c:28 Modules linked in: CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.13.0 #3 Workqueue: usb_hub_wq hub_event RIP: 0010:refcount_warn_saturate+0x18e/0x1a0 lib/refcount.c:28 Call Trace: kref_put.constprop.0+0x60/0x85 include/linux/kref.h:69 em28xx_usb_disconnect.cold+0xd7/0xdc drivers/media/usb/em28xx/em28xx-cards.c:4150 usb_unbind_interface+0xbf/0x3a0 drivers/usb/core/driver.c:458 __device_release_driver drivers/base/dd.c:1201 [inline] device_release_driver_internal+0x22a/0x230 drivers/base/dd.c:1232 bus_remove_device+0x108/0x160 drivers/base/bus.c:529 device_del+0x1fe/0x510 drivers/base/core.c:3540 usb_disable_device+0xd1/0x1d0 drivers/usb/core/message.c:1419 usb_disconnect+0x109/0x330 drivers/usb/core/hub.c:2221 hub_port_connect drivers/usb/core/hub.c:5151 [inline] hub_port_connect_change drivers/usb/core/hub.c:5440 [inline] port_event drivers/usb/core/hub.c:5586 [inline] hub_event+0xf81/0x1d40 drivers/usb/core/hub.c:5668 process_one_work+0x2c9/0x610 kernel/workqueue.c:2276 process_scheduled_works kernel/workqueue.c:2338 [inline] worker_thread+0x333/0x5b0 kernel/workqueue.c:2424 kthread+0x188/0x1d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Reported-by: Dongliang Mu mudongliangabcd@gmail.com Fixes: ac5688637144 ("media: em28xx: Fix possible memory leak of em28xx struct") Signed-off-by: Dongliang Mu mudongliangabcd@gmail.com Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/media/usb/em28xx/em28xx-input.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/media/usb/em28xx/em28xx-input.c b/drivers/media/usb/em28xx/em28xx-input.c index 3612f0d730ddd..92007a225d8ea 100644 --- a/drivers/media/usb/em28xx/em28xx-input.c +++ b/drivers/media/usb/em28xx/em28xx-input.c @@ -865,7 +865,6 @@ static int em28xx_ir_init(struct em28xx *dev) kfree(ir); ref_put: em28xx_shutdown_buttons(dev); - kref_put(&dev->ref, em28xx_free_device); return err; }