usb: core: safely deal with the dynamic quirk lists
authorHarry Pan <harry.pan@intel.com>
Fri, 14 Sep 2018 08:58:16 +0000 (16:58 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 20 Sep 2018 11:20:24 +0000 (13:20 +0200)
commit16c4cb19fa85c648a803752eb63cac0ef69231c2
treed7e8ca9c686c466d8065e3a9a9d0fe2ded2c86ea
parent5c54fcac9a9de559b444ac63ec3cd82f1d157a0b
usb: core: safely deal with the dynamic quirk lists

Applying dynamic usbcore quirks in early booting when the slab is
not yet ready would cause kernel panic of null pointer dereference
because the quirk_count has been counted as 1 while the quirk_list
was failed to allocate.

i.e.,
[    1.044970] BUG: unable to handle kernel NULL pointer dereference at           (null)
[    1.044995] IP: [<ffffffffb0953ec7>] usb_detect_quirks+0x88/0xd1
[    1.045016] PGD 0
[    1.045026] Oops: 0000 [#1] PREEMPT SMP
[    1.046986] gsmi: Log Shutdown Reason 0x03
[    1.046995] Modules linked in:
[    1.047008] CPU: 0 PID: 81 Comm: kworker/0:3 Not tainted 4.4.154 #28
[    1.047016] Hardware name: Google Coral/Coral, BIOS Google_Coral.10068.27.0 12/04/2017
[    1.047028] Workqueue: usb_hub_wq hub_event
[    1.047037] task: ffff88017a321c80 task.stack: ffff88017a384000
[    1.047044] RIP: 0010:[<ffffffffb0953ec7>]  [<ffffffffb0953ec7>] usb_detect_quirks+0x88/0xd1

To tackle this odd, let's balance the quirk_count to 0 when the kcalloc
call fails, and defer the quirk setting into a lower level callback
which ensures that the kernel memory management has been initialized.

Fixes: 027bd6cafd9a ("usb: core: Add "quirks" parameter for usbcore")
Signed-off-by: Harry Pan <harry.pan@intel.com>
Acked-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/quirks.c