PM / Hibernate: Fix memory corruption related to swap

commit c9e664f1fdf34aa8cede047b206deaa8f1945af0 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 975609cb8548504f20fd09e91476197a39dfbef1..81483c20735f3d4ad0dc805aa86d1296fd666e03 100644 (file)
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -339,7 +339,7 @@ void drain_local_pages(void *dummy);
 
 extern gfp_t gfp_allowed_mask;
 
-extern void set_gfp_allowed_mask(gfp_t mask);
-extern gfp_t clear_gfp_allowed_mask(gfp_t mask);
+extern void pm_restrict_gfp_mask(void);
+extern void pm_restore_gfp_mask(void);
 
 #endif /* __LINUX_GFP_H */

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 8dc31e02ae129e8f042804b67c38ab02f997d94c..7a931a90e4a288e42e1b4230bcb486cd83a9487b 100644 (file)
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -326,7 +326,6 @@ static int create_image(int platform_mode)
 int hibernation_snapshot(int platform_mode)
 {
        int error;
-       gfp_t saved_mask;
 
        error = platform_begin(platform_mode);
        if (error)
@@ -338,7 +337,7 @@ int hibernation_snapshot(int platform_mode)
                goto Close;
 
        suspend_console();
-       saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+       pm_restrict_gfp_mask();
        error = dpm_suspend_start(PMSG_FREEZE);
        if (error)
                goto Recover_platform;
@@ -347,7 +346,10 @@ int hibernation_snapshot(int platform_mode)
                goto Recover_platform;
 
        error = create_image(platform_mode);
-       /* Control returns here after successful restore */
+       /*
+        * Control returns here (1) after the image has been created or the
+        * image creation has failed and (2) after a successful restore.
+        */
 
  Resume_devices:
        /* We may need to release the preallocated image pages here. */
@@ -356,7 +358,10 @@ int hibernation_snapshot(int platform_mode)
 
        dpm_resume_end(in_suspend ?
                (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
-       set_gfp_allowed_mask(saved_mask);
+
+       if (error || !in_suspend)
+               pm_restore_gfp_mask();
+
        resume_console();
  Close:
        platform_end(platform_mode);
@@ -451,17 +456,16 @@ static int resume_target_kernel(bool platform_mode)
 int hibernation_restore(int platform_mode)
 {
        int error;
-       gfp_t saved_mask;
 
        pm_prepare_console();
        suspend_console();
-       saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+       pm_restrict_gfp_mask();
        error = dpm_suspend_start(PMSG_QUIESCE);
        if (!error) {
                error = resume_target_kernel(platform_mode);
                dpm_resume_end(PMSG_RECOVER);
        }
-       set_gfp_allowed_mask(saved_mask);
+       pm_restore_gfp_mask();
        resume_console();
        pm_restore_console();
        return error;
@@ -475,7 +479,6 @@ int hibernation_restore(int platform_mode)
 int hibernation_platform_enter(void)
 {
        int error;
-       gfp_t saved_mask;
 
        if (!hibernation_ops)
                return -ENOSYS;
@@ -491,7 +494,6 @@ int hibernation_platform_enter(void)
 
        entering_platform_hibernation = true;
        suspend_console();
-       saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
        error = dpm_suspend_start(PMSG_HIBERNATE);
        if (error) {
                if (hibernation_ops->recover)
@@ -535,7 +537,6 @@ int hibernation_platform_enter(void)
  Resume_devices:
        entering_platform_hibernation = false;
        dpm_resume_end(PMSG_RESTORE);
-       set_gfp_allowed_mask(saved_mask);
        resume_console();
 
  Close:
@@ -643,6 +644,7 @@ int hibernate(void)
                swsusp_free();
                if (!error)
                        power_down();
+               pm_restore_gfp_mask();
        } else {
                pr_debug("PM: Image restored successfully.\n");
        }

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 7335952ee473956e6a1e7b57f3d397220e6c5536..ecf770509d0d1bb9dce2381716d6e7583ee6c492 100644 (file)
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -197,7 +197,6 @@ static int suspend_enter(suspend_state_t state)
 int suspend_devices_and_enter(suspend_state_t state)
 {
        int error;
-       gfp_t saved_mask;
 
        if (!suspend_ops)
                return -ENOSYS;
@@ -208,7 +207,7 @@ int suspend_devices_and_enter(suspend_state_t state)
                        goto Close;
        }
        suspend_console();
-       saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+       pm_restrict_gfp_mask();
        suspend_test_start();
        error = dpm_suspend_start(PMSG_SUSPEND);
        if (error) {
@@ -225,7 +224,7 @@ int suspend_devices_and_enter(suspend_state_t state)
        suspend_test_start();
        dpm_resume_end(PMSG_RESUME);
        suspend_test_finish("resume devices");
-       set_gfp_allowed_mask(saved_mask);
+       pm_restore_gfp_mask();
        resume_console();
  Close:
        if (suspend_ops->end)

diff --git a/kernel/power/user.c b/kernel/power/user.c
index e819e17877ca9cd2540440a67919b2b019222976..1b2ea31e6bd8c0eca7eaaf985bc84337a1e750d0 100644 (file)
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -263,6 +263,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
        case SNAPSHOT_UNFREEZE:
                if (!data->frozen || data->ready)
                        break;
+               pm_restore_gfp_mask();
                thaw_processes();
                usermodehelper_enable();
                data->frozen = 0;
@@ -275,6 +276,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
                        error = -EPERM;
                        break;
                }
+               pm_restore_gfp_mask();
                error = hibernation_snapshot(data->platform_support);
                if (!error)
                        error = put_user(in_suspend, (int __user *)arg);

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8ea4d969d339e952362a4074fcdfe3f6a82111dd..2bd6f6da38ea5d93332c4bb6cb5799fcd489cb9b 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -103,19 +103,24 @@ 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 */