Skip to main content

Browse the archive

https://github.com/torvalds/linux
13 June 2022, 11:31:42 UTC
Revision 40fea92ffb5fa0ef26d10ae0fe5688bc8e61c791 authored by Stephen Boyd on 13 August 2013, 21:12:40 UTC, committed by Rafael J. Wysocki on 13 August 2013, 22:42:05 UTC 
PM / QoS: Fix workqueue deadlock when using pm_qos_update_request_timeout()
 
pm_qos_update_request_timeout() updates a qos and then schedules
a delayed work item to bring the qos back down to the default
after the timeout. When the work item runs, pm_qos_work_fn() will
call pm_qos_update_request() and deadlock because it tries to
cancel itself via cancel_delayed_work_sync(). Future callers of
that qos will also hang waiting to cancel the work that is
canceling itself. Let's extract the little bit of code that does
the real work of pm_qos_update_request() and call it from the
work function so that we don't deadlock.

Before ed1ac6e (PM: don't use [delayed_]work_pending()) this didn't
happen because the work function wouldn't try to cancel itself.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org> # 3.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 parent d4e4ab8
History
Tip revision: 40fea92ffb5fa0ef26d10ae0fe5688bc8e61c791 authored by Stephen Boyd on 13 August 2013, 21:12:40 UTC
PM / QoS: Fix workqueue deadlock when using pm_qos_update_request_timeout()
Tip revision: 40fea92
File Mode Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore -rw-r--r-- 1.1 KB
.mailmap -rw-r--r-- 4.4 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 93.1 KB
Kbuild -rw-r--r-- 2.5 KB
Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 253.9 KB
Makefile -rw-r--r-- 47.4 KB
README -rw-r--r-- 18.3 KB
REPORTING-BUGS -rw-r--r-- 7.3 KB

README

back to top