From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 16 Nov 2017 17:41:20 +0000 (+0100)
Subject: 4.9-stable patches
X-Git-Tag: v3.18.82~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c037fdb5ea59650bee3528b7732c5b5298f68aa3;p=thirdparty%2Fkernel%2Fstable-queue.git

4.9-stable patches

added patches:
	misc-panel-properly-restore-atomic-counter-on-error-path.patch
---

diff --git a/queue-4.9/misc-panel-properly-restore-atomic-counter-on-error-path.patch b/queue-4.9/misc-panel-properly-restore-atomic-counter-on-error-path.patch
new file mode 100644
index 00000000000..54909413f33
--- /dev/null
+++ b/queue-4.9/misc-panel-properly-restore-atomic-counter-on-error-path.patch
@@ -0,0 +1,78 @@
+>From 7ddfddb3fc0afb2aa36e89b554f06c901c5fa36f Mon Sep 17 00:00:00 2001
+From: Willy Tarreau <w@1wt.eu>
+Date: Thu, 7 Sep 2017 11:56:40 +0200
+Subject: misc: panel: properly restore atomic counter on error path
+
+commit 93dc1774d2a4c7a298d5cdf78cc8acdcb7b1428d upstream.
+
+Commit f4757af ("staging: panel: Fix single-open policy race condition")
+introduced in 3.19-rc1 attempted to fix a race condition on the open, but
+failed to properly do it and used to exit without restoring the semaphore.
+
+This results in -EBUSY being returned after the first open error until
+the module is reloaded or the system restarted (ie: consecutive to a
+dual open resulting in -EBUSY or to a permission error).
+
+Fixes: f4757af85 # 3.19-rc1
+Cc: Mariusz Gorski <marius.gorski@gmail.com>
+Signed-off-by: Willy Tarreau <w@1wt.eu>
+[wt: driver is in misc/panel in 4.9]
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/misc/panel.c |   23 +++++++++++++++++++----
+ 1 file changed, 19 insertions(+), 4 deletions(-)
+
+--- a/drivers/misc/panel.c
++++ b/drivers/misc/panel.c
+@@ -1423,17 +1423,25 @@ static ssize_t lcd_write(struct file *fi
+ 
+ static int lcd_open(struct inode *inode, struct file *file)
+ {
++	int ret;
++
++	ret = -EBUSY;
+ 	if (!atomic_dec_and_test(&lcd_available))
+-		return -EBUSY;	/* open only once at a time */
++		goto fail; /* open only once at a time */
+ 
++	ret = -EPERM;
+ 	if (file->f_mode & FMODE_READ)	/* device is write-only */
+-		return -EPERM;
++		goto fail;
+ 
+ 	if (lcd.must_clear) {
+ 		lcd_clear_display();
+ 		lcd.must_clear = false;
+ 	}
+ 	return nonseekable_open(inode, file);
++
++ fail:
++	atomic_inc(&lcd_available);
++	return ret;
+ }
+ 
+ static int lcd_release(struct inode *inode, struct file *file)
+@@ -1696,14 +1704,21 @@ static ssize_t keypad_read(struct file *
+ 
+ static int keypad_open(struct inode *inode, struct file *file)
+ {
++	int ret;
++
++	ret = -EBUSY;
+ 	if (!atomic_dec_and_test(&keypad_available))
+-		return -EBUSY;	/* open only once at a time */
++		goto fail;	/* open only once at a time */
+ 
++	ret = -EPERM;
+ 	if (file->f_mode & FMODE_WRITE)	/* device is read-only */
+-		return -EPERM;
++		goto fail;
+ 
+ 	keypad_buflen = 0;	/* flush the buffer on opening */
+ 	return 0;
++ fail:
++	atomic_inc(&keypad_available);
++	return ret;
+ }
+ 
+ static int keypad_release(struct inode *inode, struct file *file)
diff --git a/queue-4.9/series b/queue-4.9/series
index 0e9fa09d77b..90a0cb0b082 100644
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -36,3 +36,4 @@ security-keys-add-config_keys_compat-to-kconfig.patch
 brcmfmac-remove-setting-ibss-mode-when-stopping-ap.patch
 target-iscsi-fix-iscsi-task-reassignment-handling.patch
 qla2xxx-fix-incorrect-tcm_qla2xxx_free_cmd-use-during-tmr-abort-v2.patch
+misc-panel-properly-restore-atomic-counter-on-error-path.patch