Am Dienstag, den 02.07.2019, 18:01 -0700 schrieb syzbot: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 7829a896 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=11e19043a00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63 > dashboard link: https://syzkaller.appspot.com/bug?extid=0c90fc937c84f97d0aa6 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147d42eda00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=104c268ba00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+0c90fc937c84f97d0aa6@xxxxxxxxxxxxxxxxxxxxxxxxx > > cpia2: Message: count = 1, register[0] = 0x0 > cpia2: Unexpected error: -19 > ================================================================== > BUG: KASAN: use-after-free in cpia2_usb_disconnect+0x1a4/0x1c0 > drivers/media/usb/cpia2/cpia2_usb.c:898 > Read of size 8 at addr ffff8881cf6c4e50 by task kworker/1:1/22 Please try this: >From a0a73298fc23acb95e7b6487e960be707563eb34 Mon Sep 17 00:00:00 2001 From: Oliver Neukum <oneukum@xxxxxxxx> Date: Wed, 8 May 2019 12:36:40 +0200 Subject: [PATCH] cpia2_usb: first wake up, then free in disconnect Kasan reported a use after free in cpia2_usb_disconnect() It first freed everything and then woke up those waiting. The reverse order is correct. Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> Reported-by: syzbot+0c90fc937c84f97d0aa6@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 6c493f8b28c67 ("[media] cpia2: major overhaul to get it in a working state again") --- drivers/media/usb/cpia2/cpia2_usb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/cpia2/cpia2_usb.c b/drivers/media/usb/cpia2/cpia2_usb.c index e5d8dee38fe4..44bd7e5ad3eb 100644 --- a/drivers/media/usb/cpia2/cpia2_usb.c +++ b/drivers/media/usb/cpia2/cpia2_usb.c @@ -902,7 +902,6 @@ static void cpia2_usb_disconnect(struct usb_interface *intf) cpia2_unregister_camera(cam); v4l2_device_disconnect(&cam->v4l2_dev); mutex_unlock(&cam->v4l2_lock); - v4l2_device_put(&cam->v4l2_dev); if(cam->buffers) { DBG("Wakeup waiting processes\n"); @@ -911,6 +910,8 @@ static void cpia2_usb_disconnect(struct usb_interface *intf) wake_up_interruptible(&cam->wq_stream); } + v4l2_device_put(&cam->v4l2_dev); + LOG("CPiA2 camera disconnected.\n"); } -- 2.16.4
