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Subject[PATCH 1/3] Char: n_r3964, fix lock imbalance
Date
There is omitted BKunL in r3964_read.

Centralize the paths to one point with one unlock.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
---
drivers/char/n_r3964.c | 26 ++++++++++++++------------
1 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/char/n_r3964.c b/drivers/char/n_r3964.c
index d2e93e3..2e99158 100644
--- a/drivers/char/n_r3964.c
+++ b/drivers/char/n_r3964.c
@@ -1062,7 +1062,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
struct r3964_client_info *pClient;
struct r3964_message *pMsg;
struct r3964_client_message theMsg;
- int count;
+ int ret;

TRACE_L("read()");

@@ -1074,8 +1074,8 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
if (pMsg == NULL) {
/* no messages available. */
if (file->f_flags & O_NONBLOCK) {
- unlock_kernel();
- return -EAGAIN;
+ ret = -EAGAIN;
+ goto unlock;
}
/* block until there is a message: */
wait_event_interruptible(pInfo->read_wait,
@@ -1085,29 +1085,31 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
/* If we still haven't got a message, we must have been signalled */

if (!pMsg) {
- unlock_kernel();
- return -EINTR;
+ ret = -EINTR;
+ goto unlock;
}

/* deliver msg to client process: */
theMsg.msg_id = pMsg->msg_id;
theMsg.arg = pMsg->arg;
theMsg.error_code = pMsg->error_code;
- count = sizeof(struct r3964_client_message);
+ ret = sizeof(struct r3964_client_message);

kfree(pMsg);
TRACE_M("r3964_read - msg kfree %p", pMsg);

- if (copy_to_user(buf, &theMsg, count)) {
- unlock_kernel();
- return -EFAULT;
+ if (copy_to_user(buf, &theMsg, ret)) {
+ ret = -EFAULT;
+ goto unlock;
}

- TRACE_PS("read - return %d", count);
- return count;
+ TRACE_PS("read - return %d", ret);
+ goto unlock;
}
+ ret = -EPERM;
+unlock:
unlock_kernel();
- return -EPERM;
+ return ret;
}

static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
--
1.6.3.2


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