linux/include
Tejun Heo cd924e960d freezer: add missing mb's to freezer_count() and freezer_should_skip()
commit dd67d32dbc upstream.

A task is considered frozen enough between freezer_do_not_count() and
freezer_count() and freezers use freezer_should_skip() to test this
condition.  This supposedly works because freezer_count() always calls
try_to_freezer() after clearing %PF_FREEZER_SKIP.

However, there currently is nothing which guarantees that
freezer_count() sees %true freezing() after clearing %PF_FREEZER_SKIP
when freezing is in progress, and vice-versa.  A task can escape the
freezing condition in effect by freezer_count() seeing !freezing() and
freezer_should_skip() seeing %PF_FREEZER_SKIP.

This patch adds smp_mb()'s to freezer_count() and
freezer_should_skip() such that either %true freezing() is visible to
freezer_count() or !PF_FREEZER_SKIP is visible to
freezer_should_skip().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-11 09:06:58 -08:00
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-05-05 10:06:06 -07:00
asm-generic mutex: Place lock in contended state after fastpath_lock failure 2012-10-02 10:30:21 -07:00
crypto crypto: user - Fix lookup of algorithms with IV generator 2012-03-29 19:52:47 +08:00
drm drm/radeon: add new SI pci id 2012-12-03 11:47:01 -08:00
keys keys: add a "logon" key type 2012-01-17 22:39:40 -06:00
linux freezer: add missing mb's to freezer_count() and freezer_should_skip() 2013-01-11 09:06:58 -08:00
math-emu
media Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2012-05-14 11:23:37 -07:00
misc
mtd
net mac80211: verify that skb data is present 2012-11-17 13:16:11 -08:00
pcmcia
rdma infiniband: pass rdma_cm module to netlink_dump_start 2012-10-28 10:14:15 -07:00
rxrpc
scsi SCSI: libsas: fix taskfile corruption in sas_ata_qc_fill_rtf 2012-07-16 09:04:37 -07:00
sound ALSA: Add a reference counter to card instance 2012-11-17 13:16:13 -08:00
target target: Add generation of LOGICAL BLOCK ADDRESS OUT OF RANGE 2012-08-09 08:31:26 -07:00
trace xen/mmu: Use Xen specific TLB flush instead of the generic one. 2012-11-17 13:15:54 -08:00
video Merge branch 'platforms' of git://git.linaro.org/people/rmk/linux-arm 2012-03-27 18:17:02 -07:00
xen xen/m2p: do not reuse kmap_op->dev_bus_addr 2012-10-02 10:30:06 -07:00
Kbuild