[PATCH] swsusp: add locking to software_resume
It is trying to protect swsusp_resume_device and software_resume() from two
users banging it from userspace at the same time.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 664eb04..88beec6 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -233,9 +233,12 @@
{
int error;
+ down(&pm_sem);
if (!swsusp_resume_device) {
- if (!strlen(resume_file))
+ if (!strlen(resume_file)) {
+ up(&pm_sem);
return -ENOENT;
+ }
swsusp_resume_device = name_to_dev_t(resume_file);
pr_debug("swsusp: Resume From Partition %s\n", resume_file);
} else {
@@ -248,6 +251,7 @@
* FIXME: If noresume is specified, we need to find the partition
* and reset it back to normal swap space.
*/
+ up(&pm_sem);
return 0;
}
@@ -284,6 +288,8 @@
Cleanup:
unprepare_processes();
Done:
+ /* For success case, the suspend path will release the lock */
+ up(&pm_sem);
pr_debug("PM: Resume from disk failed.\n");
return 0;
}
@@ -390,7 +396,9 @@
if (sscanf(buf, "%u:%u", &maj, &min) == 2) {
res = MKDEV(maj,min);
if (maj == MAJOR(res) && min == MINOR(res)) {
+ down(&pm_sem);
swsusp_resume_device = res;
+ up(&pm_sem);
printk("Attempting manual resume\n");
noresume = 0;
software_resume();