c0317c0e87
When the timer instance was add into ack_list but was not currently in process, the user could stop it via snd_timer_stop1() without delete it from the ack_list. Then the user could free the timer instance and when it was actually processed UAF occurred. This issue could be reproduced via testcase snd_timer01 in ltp - running several instances of that testcase at the same time. What I actually met was that the ack_list of the timer broken and the kernel went into deadloop with irqoff. That could be detected by hardlockup detector on board or when we run it on qemu, we could use gdb to dump the ack_list when the console has no response. To fix this issue, we delete the timer instance from ack_list and active_list unconditionally in snd_timer_stop1(). Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com> Suggested-by: Takashi Iwai <tiwai@suse.de> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20211103033517.80531-1-wangwensheng4@huawei.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
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.