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Message-Id: <20190213183707.462377925@linuxfoundation.org>
Date: Wed, 13 Feb 2019 19:38:26 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mike Christie <mchristi@...hat.com>,
Hamish Martin <hamish.martin@...iedtelesis.co.nz>,
Xiubo Li <xiubli@...hat.com>,
Tommi Rantala <tommi.t.rantala@...ia.com>
Subject: [PATCH 4.14 31/35] uio: change to use the mutex lock instead of the spin lock
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xiubo Li <xiubli@...hat.com>
commit 543af5861f41af0a5d2432f6fb5976af50f9cee5 upstream.
We are hitting a regression with the following commit:
commit a93e7b331568227500186a465fee3c2cb5dffd1f
Author: Hamish Martin <hamish.martin@...iedtelesis.co.nz>
Date: Mon May 14 13:32:23 2018 +1200
uio: Prevent device destruction while fds are open
The problem is the addition of spin_lock_irqsave in uio_write. This
leads to hitting uio_write -> copy_from_user -> _copy_from_user ->
might_fault and the logs filling up with sleeping warnings.
I also noticed some uio drivers allocate memory, sleep, grab mutexes
from callouts like open() and release and uio is now doing
spin_lock_irqsave while calling them.
Reported-by: Mike Christie <mchristi@...hat.com>
CC: Hamish Martin <hamish.martin@...iedtelesis.co.nz>
Reviewed-by: Hamish Martin <hamish.martin@...iedtelesis.co.nz>
Signed-off-by: Xiubo Li <xiubli@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Tommi Rantala <tommi.t.rantala@...ia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/uio/uio.c | 32 +++++++++++++-------------------
include/linux/uio_driver.h | 2 +-
2 files changed, 14 insertions(+), 20 deletions(-)
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -435,7 +435,6 @@ static int uio_open(struct inode *inode,
struct uio_device *idev;
struct uio_listener *listener;
int ret = 0;
- unsigned long flags;
mutex_lock(&minor_lock);
idev = idr_find(&uio_idr, iminor(inode));
@@ -462,10 +461,10 @@ static int uio_open(struct inode *inode,
listener->event_count = atomic_read(&idev->event);
filep->private_data = listener;
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
if (idev->info && idev->info->open)
ret = idev->info->open(idev->info, inode);
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
if (ret)
goto err_infoopen;
@@ -497,12 +496,11 @@ static int uio_release(struct inode *ino
int ret = 0;
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
- unsigned long flags;
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
if (idev->info && idev->info->release)
ret = idev->info->release(idev->info, inode);
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
module_put(idev->owner);
kfree(listener);
@@ -515,12 +513,11 @@ static unsigned int uio_poll(struct file
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;
unsigned int ret = 0;
- unsigned long flags;
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
if (!idev->info || !idev->info->irq)
ret = -EIO;
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
if (ret)
return ret;
@@ -539,12 +536,11 @@ static ssize_t uio_read(struct file *fil
DECLARE_WAITQUEUE(wait, current);
ssize_t retval = 0;
s32 event_count;
- unsigned long flags;
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
if (!idev->info || !idev->info->irq)
retval = -EIO;
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
if (retval)
return retval;
@@ -594,9 +590,8 @@ static ssize_t uio_write(struct file *fi
struct uio_device *idev = listener->dev;
ssize_t retval;
s32 irq_on;
- unsigned long flags;
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
if (!idev->info || !idev->info->irq) {
retval = -EIO;
goto out;
@@ -620,7 +615,7 @@ static ssize_t uio_write(struct file *fi
retval = idev->info->irqcontrol(idev->info, irq_on);
out:
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
return retval ? retval : sizeof(s32);
}
@@ -874,7 +869,7 @@ int __uio_register_device(struct module
idev->owner = owner;
idev->info = info;
- spin_lock_init(&idev->info_lock);
+ mutex_init(&idev->info_lock);
init_waitqueue_head(&idev->wait);
atomic_set(&idev->event, 0);
@@ -940,7 +935,6 @@ EXPORT_SYMBOL_GPL(__uio_register_device)
void uio_unregister_device(struct uio_info *info)
{
struct uio_device *idev;
- unsigned long flags;
if (!info || !info->uio_dev)
return;
@@ -954,9 +948,9 @@ void uio_unregister_device(struct uio_in
if (info->irq && info->irq != UIO_IRQ_CUSTOM)
free_irq(info->irq, idev);
- spin_lock_irqsave(&idev->info_lock, flags);
+ mutex_lock(&idev->info_lock);
idev->info = NULL;
- spin_unlock_irqrestore(&idev->info_lock, flags);
+ mutex_unlock(&idev->info_lock);
device_unregister(&idev->dev);
--- a/include/linux/uio_driver.h
+++ b/include/linux/uio_driver.h
@@ -75,7 +75,7 @@ struct uio_device {
struct fasync_struct *async_queue;
wait_queue_head_t wait;
struct uio_info *info;
- spinlock_t info_lock;
+ struct mutex info_lock;
struct kobject *map_dir;
struct kobject *portio_dir;
};
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