8b66eec1fd
As &info->lock is acquired by slgt_interrupt() under irq context, other
process context code acquiring the lock should disable irq, otherwise
deadlock could happen if the irq preempt the execution while the
lock is held in process context on the same CPU.
Lock acquisition inside set_params32() does not disable irq, and this
function is called by slgt_compat_ioctl() from process context.
Possible deadlock scenario:
slgt_compat_ioctl()
-> set_params32()
-> spin_lock(&info->lock)
<irq>
-> slgt_interrupt()
-> spin_lock(&info->lock); (deadlock here)
This flaw was found by an experimental static analysis tool I am developing
for irq-related deadlock. x86_64 allmodconfig using gcc shows no new
warning.
The patch fixes the potential deadlock by spin_lock_irqsave() like other
lock acquisition sites.
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230728123901.64225-1-dg573847474@gmail.com
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.