diff options
| author | Andrei Vagin <avagin@openvz.org> | 2017-01-04 19:28:14 -0800 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2017-01-10 13:34:56 +1300 |
| commit | add7c65ca426b7a37184dd3d2172394e23d585d6 (patch) | |
| tree | 28b08b519540041b06ed0ab0b1c005076b932e8e /include/xen/events.h | |
| parent | 75422726b0f717d67db3283c2eb5bc14fa2619c5 (diff) | |
pid: fix lockdep deadlock warning due to ucount_lock
=========================================================
[ 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: f333c700c610 ("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>
Diffstat (limited to 'include/xen/events.h')