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commit a4b46d450c49f32e9d4247b421e58083fde304ce upstream. Testing with KASAN and syzkaller revealed a bug in port.c:disable_store(): usb_hub_to_struct_hub() can return NULL if the hub that the port belongs to is concurrently removed, but the function does not check for this possibility before dereferencing the returned value. It turns out that the first dereference is unnecessary, since hub->intfdev is the parent of the port device, so it can be changed easily. Adding a check for hub == NULL prevents further problems. The same bug exists in the disable_show() routine, and it can be fixed the same way. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: Yue Sun <samsun1006219@gmail.com> Reported-by: xingwei lee <xrivendell7@gmail.com> Link: https://lore.kernel.org/linux-usb/CAEkJfYON+ry7xPx=AiLR9jzUNT+i_Va68ACajOC3HoacOfL1ig@mail.gmail.com/ Fixes: f061f43d7418 ("usb: hub: port: add sysfs entry to switch port power") CC: Michael Grzeschik <m.grzeschik@pengutronix.de> CC: stable@vger.kernel.org Link: https://lore.kernel.org/r/393aa580-15a5-44ca-ad3b-6462461cd313@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.