This is a note to let you know that I've just added the patch titled
fbdev: flush deferred IO before closing
to the 6.1-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:
fbdev-flush-deferred-io-before-closing.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 33cd6ea9c0673517cdb06ad5c915c6f22e9615fc Mon Sep 17 00:00:00 2001
From: Nam Cao <namcao@xxxxxxxxxxxxx>
Date: Mon, 18 Dec 2023 10:57:31 +0100
Subject: fbdev: flush deferred IO before closing
From: Nam Cao <namcao@xxxxxxxxxxxxx>
commit 33cd6ea9c0673517cdb06ad5c915c6f22e9615fc upstream.
When framebuffer gets closed, the queued deferred IO gets cancelled. This
can cause some last display data to vanish. This is problematic for users
who send a still image to the framebuffer, then close the file: the image
may never appear.
To ensure none of display data get lost, flush the queued deferred IO
first before closing.
Another possible solution is to delete the cancel_delayed_work_sync()
instead. The difference is that the display may appear some time after
closing. However, the clearing of page mapping after this needs to be
removed too, because the page mapping is used by the deferred work. It is
not completely obvious whether it is okay to not clear the page mapping.
For a patch intended for stable trees, go with the simple and obvious
solution.
Fixes: 60b59beafba8 ("fbdev: mm: Deferred IO support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Nam Cao <namcao@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/core/fb_defio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -317,7 +317,7 @@ static void fb_deferred_io_lastclose(str
struct page *page;
int i;
- cancel_delayed_work_sync(&info->deferred_work);
+ flush_delayed_work(&info->deferred_work);
/* clear out the mapping that we setup */
for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
Patches currently in stable-queue which might be from namcao@xxxxxxxxxxxxx are
queue-6.1/fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch
queue-6.1/fbdev-flush-deferred-io-before-closing.patch
