28a45ef85e
&qs->qs_lock is acquired by timer o2net_idle_timer() along the following
call chain. Thus the acquisition of the lock under process context should
disable bottom half, otherwise deadlock could happen if the timer happens
to preempt the execution while the lock is held in process context on the
same CPU.
<timer interrupt>
-> o2net_idle_timer()
-> o2quo_conn_err()
-> spin_lock(&qs->qs_lock)
Several lock acquisition of &qs->qs_lock under process contex do not
disable irq or bottom half. The patch fixes these potential deadlocks
scenerio by using spin_lock_bh() on &qs->qs_lock.
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.
Link: https://lkml.kernel.org/r/20230802123824.15301-1-dg573847474@gmail.com
Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.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.