Am Mittwoch, den 07.08.2019, 16:03 +0200 schrieb Andrey Konovalov:
I may offer a preliminary analysis.
Regards
Oliver
> On Fri, Apr 12, 2019 at 1:32 PM Andrey Konovalov <andreyk...@google.com>
> wrote:
> >
> > On Fri, Apr 12, 2019 at 1:29 AM syzbot
> > <syzbot+40918e4d826fb2ff9...@syzkaller.appspotmail.com> wrote:
> > >
> > > syzbot has found a reproducer for the following crash on:
> > >
> > > HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver
> > > git tree: https://github.com/google/kasan/tree/usb-fuzzer
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=10d552b7200000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15
> > > dashboard link:
> > > https://syzkaller.appspot.com/bug?extid=40918e4d826fb2ff9b96
> > > compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17a4c1af200000
> > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=121b274b200000
> > >
> > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > Reported-by: syzbot+40918e4d826fb2ff9...@syzkaller.appspotmail.com
> > >
> > > usb 1-1: r8712u: MAC Address from efuse = 00:e0:4c:87:00:00
> > > usb 1-1: r8712u: Loading firmware from "rtlwifi/rtl8712u.bin"
> > > usb 1-1: USB disconnect, device number 2
Disconnect will run which leads to
static void r871xu_dev_remove(struct usb_interface *pusb_intf)
{
struct net_device *pnetdev = usb_get_intfdata(pusb_intf);
struct usb_device *udev = interface_to_usbdev(pusb_intf);
if (pnetdev) {
^^^ This is supposed to save us
struct _adapter *padapter = netdev_priv(pnetdev);
usb_set_intfdata(pusb_intf, NULL);
release_firmware(padapter->fw);
/* never exit with a firmware callback pending */
wait_for_completion(&padapter->rtl8712_fw_ready);
if (drvpriv.drv_registered)
padapter->surprise_removed = true;
unregister_netdev(pnetdev); /* will call netdev_close() */
So we will call unregister_netdev()
> > > usb 1-1: Direct firmware load for rtlwifi/rtl8712u.bin failed with error
> > > -2
> > > usb 1-1: r8712u: Firmware request failed
So we ran into the error handling of:
static void rtl871x_load_fw_cb(const struct firmware *firmware, void *context)
{
struct _adapter *adapter = context;
complete(&adapter->rtl8712_fw_ready);
if (!firmware) {
struct usb_device *udev = adapter->dvobjpriv.pusbdev;
struct usb_interface *usb_intf = adapter->pusb_intf;
dev_err(&udev->dev, "r8712u: Firmware request failed\n");
usb_put_dev(udev);
usb_set_intfdata(usb_intf, NULL);
^^^ This is supposed to save us from deregistering an unregistered device
but it comes too late. We have already called complete.
return;
}
adapter->fw = firmware;
/* firmware available - start netdev */
register_netdev(adapter->pnetdev);
register_netdev() is not called.
> > > Kernel panic - not syncing: panic_on_warn set ...
> > > CPU: 0 PID: 575 Comm: kworker/0:4 Not tainted 5.1.0-rc4-319354-g9a33b36 #3
> > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > > Google 01/01/2011
> > > Workqueue: usb_hub_wq hub_event
> > > Call Trace:
> > > __dump_stack lib/dump_stack.c:77 [inline]
> > > dump_stack+0xe8/0x16e lib/dump_stack.c:113
> > > panic+0x29d/0x5f2 kernel/panic.c:214
> > > __warn.cold+0x20/0x48 kernel/panic.c:571
> > > report_bug+0x262/0x2a0 lib/bug.c:186
> > > fixup_bug arch/x86/kernel/traps.c:179 [inline]
> > > fixup_bug arch/x86/kernel/traps.c:174 [inline]
> > > do_error_trap+0x130/0x1f0 arch/x86/kernel/traps.c:272
> > > do_invalid_op+0x37/0x40 arch/x86/kernel/traps.c:291
> > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
This kills us.
> > > RIP: 0010:rollback_registered_many+0x1f3/0xe70 net/core/dev.c:8152
> > > Code: 05 00 00 31 ff 44 89 fe e8 5a 15 f3 f4 45 84 ff 0f 85 49 ff ff ff e8
> > > 1c 14 f3 f4 0f 1f 44 00 00 e8 12 14 f3 f4 e8 0d 14 f3 f4 <0f> 0b 4c 89 e7
> > > e8 33 72 f2 f6 31 ff 41 89 c4 89 c6 e8 27 15 f3 f4
> > > RSP: 0018:ffff88809d087698 EFLAGS: 00010293
> > > RAX: ffff88809d058000 RBX: ffff888096240000 RCX: ffffffff8c7eb146
> > > RDX: 0000000000000000 RSI: ffffffff8c7eb163 RDI: 0000000000000001
> > > RBP: ffff88809d0877c8 R08: ffff88809d058000 R09: fffffbfff2708111
> > > R10: fffffbfff2708110 R11: ffffffff93840887 R12: ffff888096240070
> > > R13: dffffc0000000000 R14: ffff88809d087758 R15: 0000000000000000
> > > rollback_registered+0xf7/0x1c0 net/core/dev.c:8228
> > > unregister_netdevice_queue net/core/dev.c:9275 [inline]
> > > unregister_netdevice_queue+0x1dc/0x2b0 net/core/dev.c:9268
> > > unregister_netdevice include/linux/netdevice.h:2655 [inline]
> > > unregister_netdev+0x1d/0x30 net/core/dev.c:9316
> > > r871xu_dev_remove+0xe7/0x223 drivers/staging/rtl8712/usb_intf.c:604
We end up here:
static void rollback_registered_many(struct list_head *head)
{
struct net_device *dev, *tmp;
LIST_HEAD(close_head);
BUG_ON(dev_boot_phase);
ASSERT_RTNL();
list_for_each_entry_safe(dev, tmp, head, unreg_list) {
/* Some devices call without registering
* for initialization unwind. Remove those
* devices and proceed with the remaining.
*/
if (dev->reg_state == NETREG_UNINITIALIZED) {
pr_debug("unregister_netdevice: device %s/%p never was
registered\n",
dev->name, dev);
WARN_ON(1);
