From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45028 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932107AbdJJPMo (ORCPT ); Tue, 10 Oct 2017 11:12:44 -0400 Subject: Patch "auxdisplay: charlcd: properly restore atomic counter on error path" has been added to the 4.13-stable tree To: w@1wt.eu, geert@linux-m68k.org, gregkh@linuxfoundation.org, marius.gorski@gmail.com, miguel.ojeda.sandonis@gmail.com Cc: , From: Date: Tue, 10 Oct 2017 17:12:47 +0200 Message-ID: <150764836714248@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled auxdisplay: charlcd: properly restore atomic counter on error path to the 4.13-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: auxdisplay-charlcd-properly-restore-atomic-counter-on-error-path.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 93dc1774d2a4c7a298d5cdf78cc8acdcb7b1428d Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Thu, 7 Sep 2017 15:37:30 +0200 Subject: auxdisplay: charlcd: properly restore atomic counter on error path From: Willy Tarreau 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). [ Note for stable maintainers: the code moved from drivers/misc/panel.c to drivers/auxdisplay/{charlcd,panel}.c during 4.12. The patch easily applies there (modulo the renamed atomic counter) but I can provide a tested backport if desired. ] Fixes: f4757af85 # 3.19-rc1 Cc: Mariusz Gorski Cc: Geert Uytterhoeven Cc: Miguel Ojeda Sandonis Signed-off-by: Willy Tarreau Signed-off-by: Greg Kroah-Hartman --- drivers/auxdisplay/charlcd.c | 11 +++++++++-- drivers/auxdisplay/panel.c | 11 +++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-) --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -647,18 +647,25 @@ static ssize_t charlcd_write(struct file static int charlcd_open(struct inode *inode, struct file *file) { struct charlcd_priv *priv = to_priv(the_charlcd); + int ret; + ret = -EBUSY; if (!atomic_dec_and_test(&charlcd_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 (priv->must_clear) { charlcd_clear_display(&priv->lcd); priv->must_clear = false; } return nonseekable_open(inode, file); + + fail: + atomic_inc(&charlcd_available); + return ret; } static int charlcd_release(struct inode *inode, struct file *file) --- a/drivers/auxdisplay/panel.c +++ b/drivers/auxdisplay/panel.c @@ -1105,14 +1105,21 @@ 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) Patches currently in stable-queue which might be from w@1wt.eu are queue-4.13/auxdisplay-charlcd-properly-restore-atomic-counter-on-error-path.patch