Patch "PM: hibernate: Fix the exclusive get block device in test_resume mode" has been added to the 6.5-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    PM: hibernate: Fix the exclusive get block device in test_resume mode

to the 6.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pm-hibernate-fix-the-exclusive-get-block-device-in-t.patch
and it can be found in the queue-6.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2750b0f1d2bc30185cc1c6d1a6ade999dc0190e2
Author: Chen Yu <yu.c.chen@xxxxxxxxx>
Date:   Wed Sep 6 12:18:52 2023 +0800

    PM: hibernate: Fix the exclusive get block device in test_resume mode
    
    [ Upstream commit 148b6f4cc3920e563094540fe1a12d00d3bbccae ]
    
    Commit 5904de0d735b ("PM: hibernate: Do not get block device exclusively
    in test_resume mode") fixes a hibernation issue under test_resume mode.
    That commit is supposed to open the block device in non-exclusive mode
    when in test_resume. However the code does the opposite, which is against
    its description.
    
    In summary, the swap device is only opened exclusively by swsusp_check()
    with its corresponding *close(), and must be in non test_resume mode.
    This is to avoid the race condition that different processes scribble the
    device at the same time. All the other cases should use non-exclusive mode.
    
    Fix it by really disabling exclusive mode under test_resume.
    
    Fixes: 5904de0d735b ("PM: hibernate: Do not get block device exclusively in test_resume mode")
    Closes: https://lore.kernel.org/lkml/000000000000761f5f0603324129@xxxxxxxxxx/
    Reported-by: Pengfei Xu <pengfei.xu@xxxxxxxxx>
    Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
    Tested-by: Chenzhou Feng <chenzhoux.feng@xxxxxxxxx>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 2b4a946a6ff5c..8d35b9f9aaa3f 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -786,9 +786,9 @@ int hibernate(void)
 	unlock_device_hotplug();
 	if (snapshot_test) {
 		pm_pr_dbg("Checking hibernation image\n");
-		error = swsusp_check(snapshot_test);
+		error = swsusp_check(false);
 		if (!error)
-			error = load_image_and_restore(snapshot_test);
+			error = load_image_and_restore(false);
 	}
 	thaw_processes();
 
@@ -945,14 +945,14 @@ static int software_resume(void)
 	pm_pr_dbg("Looking for hibernation image.\n");
 
 	mutex_lock(&system_transition_mutex);
-	error = swsusp_check(false);
+	error = swsusp_check(true);
 	if (error)
 		goto Unlock;
 
 	/* The snapshot device should not be opened while we're running */
 	if (!hibernate_acquire()) {
 		error = -EBUSY;
-		swsusp_close(false);
+		swsusp_close(true);
 		goto Unlock;
 	}
 
@@ -973,7 +973,7 @@ static int software_resume(void)
 		goto Close_Finish;
 	}
 
-	error = load_image_and_restore(false);
+	error = load_image_and_restore(true);
 	thaw_processes();
  Finish:
 	pm_notifier_call_chain(PM_POST_RESTORE);
@@ -987,7 +987,7 @@ static int software_resume(void)
 	pm_pr_dbg("Hibernation image not present or could not be loaded.\n");
 	return error;
  Close_Finish:
-	swsusp_close(false);
+	swsusp_close(true);
 	goto Finish;
 }