add7c65ca4
=========================================================
[ INFO: possible irq lock inversion dependency detected ]
4.10.0-rc2-00024-g4aecec9-dirty #118 Tainted: G W
---------------------------------------------------------
swapper/1/0 just changed the state of lock:
(&(&sighand->siglock)->rlock){-.....}, at: [<ffffffffbd0a1bc6>] __lock_task_sighand+0xb6/0x2c0
but this lock took another, HARDIRQ-unsafe lock in the past:
(ucounts_lock){+.+...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Chain exists of: &(&sighand->siglock)->rlock --> &(&tty->ctrl_lock)->rlock --> ucounts_lock
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(ucounts_lock);
local_irq_disable();
lock(&(&sighand->siglock)->rlock);
lock(&(&tty->ctrl_lock)->rlock);
<Interrupt>
lock(&(&sighand->siglock)->rlock);
*** DEADLOCK ***
This patch removes a dependency between rlock and ucount_lock.
Fixes: f333c700c6 ("pidns: Add a limit on the number of pid namespaces")
Cc: stable@vger.kernel.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.