4.19-stable patches

added patches:
	fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch

diff --git a/queue-4.19/fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch b/queue-4.19/fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch
new file mode 100644 (file)
index 0000000..ffdabce
--- /dev/null
+++ b/queue-4.19/fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch
@@ -0,0 +1,51 @@
+From 15e4c1f462279b4e128f27de48133e0debe9e0df Mon Sep 17 00:00:00 2001
+From: Nam Cao <namcao@linutronix.de>
+Date: Mon, 18 Dec 2023 10:57:30 +0100
+Subject: fbdev: flush deferred work in fb_deferred_io_fsync()
+
+From: Nam Cao <namcao@linutronix.de>
+
+commit 15e4c1f462279b4e128f27de48133e0debe9e0df upstream.
+
+The driver's fsync() is supposed to flush any pending operation to
+hardware. It is implemented in this driver by cancelling the queued
+deferred IO first, then schedule it for "immediate execution" by calling
+schedule_delayed_work() again with delay=0. However, setting delay=0
+only means the work is scheduled immediately, it does not mean the work
+is executed immediately. There is no guarantee that the work is finished
+after schedule_delayed_work() returns. After this driver's fsync()
+returns, there can still be pending work. Furthermore, if close() is
+called by users immediately after fsync(), the pending work gets
+cancelled and fsync() may do nothing.
+
+To ensure that the deferred IO completes, use flush_delayed_work()
+instead. Write operations to this driver either write to the device
+directly, or invoke schedule_delayed_work(); so by flushing the
+workqueue, it can be guaranteed that all previous writes make it to the
+device.
+
+Fixes: 5e841b88d23d ("fb: fsync() method for deferred I/O flush.")
+Cc: stable@vger.kernel.org
+Signed-off-by: Nam Cao <namcao@linutronix.de>
+Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Helge Deller <deller@gmx.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/video/fbdev/core/fb_defio.c |    6 +-----
+ 1 file changed, 1 insertion(+), 5 deletions(-)
+
+--- a/drivers/video/fbdev/core/fb_defio.c
++++ b/drivers/video/fbdev/core/fb_defio.c
+@@ -78,11 +78,7 @@ int fb_deferred_io_fsync(struct file *fi
+               return 0;
+ 
+       inode_lock(inode);
+-      /* Kill off the delayed work */
+-      cancel_delayed_work_sync(&info->deferred_work);
+-
+-      /* Run it immediately */
+-      schedule_delayed_work(&info->deferred_work, 0);
++      flush_delayed_work(&info->deferred_work);
+       inode_unlock(inode);
+ 
+       return 0;

diff --git a/queue-4.19/series b/queue-4.19/series
index 3f4e228468dc5c8468af54c266a2004ce1ab8470..cd1807757d974d55477b91ef3a951c6bebfecc94 100644 (file)
--- a/queue-4.19/series
+++ b/queue-4.19/series
@@ -125,3 +125,4 @@ revert-usb-typec-class-fix-typec_altmode_put_partner-to-put-plugs.patch
 usb-typec-class-fix-typec_altmode_put_partner-to-put-plugs.patch
 usb-mon-fix-atomicity-violation-in-mon_bin_vma_fault.patch
 alsa-oxygen-fix-right-channel-of-capture-volume-mixer.patch
+fbdev-flush-deferred-work-in-fb_deferred_io_fsync.patch