012936502a
[ Upstream commit d28f4091ea7ec3510fd6a3c6d433234e7a2bef14 ]
When handle qmu transfer irq, it will unlock @mtu->lock before give back
request, if another thread handle disconnect event at the same time, and
try to disable ep, it may lock @mtu->lock and free qmu ring, then qmu
irq hanlder may get a NULL gpd, avoid the KE by checking gpd's value before
handling it.
e.g.
qmu done irq on cpu0 thread running on cpu1
qmu_done_tx()
handle gpd [0]
mtu3_requ_complete() mtu3_gadget_ep_disable()
unlock @mtu->lock
give back request lock @mtu->lock
mtu3_ep_disable()
mtu3_gpd_ring_free()
unlock @mtu->lock
lock @mtu->lock
get next gpd [1]
[1]: goto [0] to handle next gpd, and next gpd may be NULL.
Fixes: 48e0d3735aa5 ("usb: mtu3: supports new QMU format")
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20230417025203.18097-3-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.