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authorRafael J. Wysocki <rjw@sisk.pl>2010-12-03 22:57:45 +0100
committerRafael J. Wysocki <rjw@sisk.pl>2010-12-06 23:52:08 +0100
commitc9e664f1fdf34aa8cede047b206deaa8f1945af0 (patch)
tree6038002f46173ca785936ac2fe54177197f98a08 /mm/page_alloc.c
parent9f339caf8454f0c21983111350ede93983db4340 (diff)
downloadlinux-c9e664f1fdf34aa8cede047b206deaa8f1945af0.tar.bz2
PM / Hibernate: Fix memory corruption related to swap
There is a problem that swap pages allocated before the creation of a hibernation image can be released and used for storing the contents of different memory pages while the image is being saved. Since the kernel stored in the image doesn't know of that, it causes memory corruption to occur after resume from hibernation, especially on systems with relatively small RAM that need to swap often. This issue can be addressed by keeping the GFP_IOFS bits clear in gfp_allowed_mask during the entire hibernation, including the saving of the image, until the system is finally turned off or the hibernation is aborted. Unfortunately, for this purpose it's necessary to rework the way in which the hibernate and suspend code manipulates gfp_allowed_mask. This change is based on an earlier patch from Hugh Dickins. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reported-by: Ondrej Zary <linux@rainbow-software.org> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: stable@kernel.org
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e4092704c1a9..ff7e15872398 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -104,19 +104,24 @@ gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
* only be modified with pm_mutex held, unless the suspend/hibernate code is
* guaranteed not to run in parallel with that modification).
*/
-void set_gfp_allowed_mask(gfp_t mask)
+
+static gfp_t saved_gfp_mask;
+
+void pm_restore_gfp_mask(void)
{
WARN_ON(!mutex_is_locked(&pm_mutex));
- gfp_allowed_mask = mask;
+ if (saved_gfp_mask) {
+ gfp_allowed_mask = saved_gfp_mask;
+ saved_gfp_mask = 0;
+ }
}
-gfp_t clear_gfp_allowed_mask(gfp_t mask)
+void pm_restrict_gfp_mask(void)
{
- gfp_t ret = gfp_allowed_mask;
-
WARN_ON(!mutex_is_locked(&pm_mutex));
- gfp_allowed_mask &= ~mask;
- return ret;
+ WARN_ON(saved_gfp_mask);
+ saved_gfp_mask = gfp_allowed_mask;
+ gfp_allowed_mask &= ~GFP_IOFS;
}
#endif /* CONFIG_PM_SLEEP */