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mei: fix double freeing of a cb during link reset 

Fix double freeing of the cb that can happen if link reset kicks  in the
middle of blocked write from a device on the cl bus.

Free cb inside mei_cl_write function on failure and drop cb free
operation from callers, during a link reset the mei_cl_write function
returns with an error,  but the caller doesn't know if the cb was
already queued or not so it doesn't know if the cb will be freed upon
queue reclaim or it has to free it itself.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Usyskin 2016-02-10 23:57:26 +02:00 committed by Greg Kroah-Hartman
parent 3ca9b1ac28
commit 6cbb097fd3
3 changed files with 14 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/misc/mei/bus.c
View File

@ -44,7 +44,7 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
bool blocking)
{
struct mei_device *bus;
struct mei_cl_cb *cb = NULL;
struct mei_cl_cb *cb;
ssize_t rets;
if (WARN_ON(!cl || !cl->dev))
@ -86,8 +86,6 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
out:
mutex_unlock(&bus->device_lock);
if (rets < 0)
mei_io_cb_free(cb);
return rets;
}

4
drivers/misc/mei/client.c
View File

@ -1645,7 +1645,7 @@ int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
if (rets < 0 && rets != -EINPROGRESS) {
pm_runtime_put_noidle(dev->dev);
cl_err(dev, cl, "rpm: get failed %d\n", rets);
return rets;
goto free;
}
cb->buf_idx = 0;
@ -1724,6 +1724,8 @@ err:
cl_dbg(dev, cl, "rpm: autosuspend\n");
pm_runtime_mark_last_busy(dev->dev);
pm_runtime_put_autosuspend(dev->dev);
free:
mei_io_cb_free(cb);
return rets;
}

26
drivers/misc/mei/main.c
View File

@ -267,7 +267,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
size_t length, loff_t *offset)
{
struct mei_cl *cl = file->private_data;
struct mei_cl_cb *write_cb = NULL;
struct mei_cl_cb *cb;
struct mei_device *dev;
int rets;
@ -305,36 +305,30 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
}
*offset = 0;
write_cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, file);
if (!write_cb) {
cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, file);
if (!cb) {
rets = -ENOMEM;
goto out;
}
rets = copy_from_user(write_cb->buf.data, ubuf, length);
rets = copy_from_user(cb->buf.data, ubuf, length);
if (rets) {
dev_dbg(dev->dev, "failed to copy data from userland\n");
rets = -EFAULT;
mei_io_cb_free(cb);
goto out;
}
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_write(cl, write_cb);
if (rets) {
dev_err(dev->dev,
"amthif write failed with status = %d\n", rets);
goto out;
}
mutex_unlock(&dev->device_lock);
return length;
rets = mei_amthif_write(cl, cb);
if (!rets)
rets = length;
goto out;
}
rets = mei_cl_write(cl, write_cb, false);
rets = mei_cl_write(cl, cb, false);
out:
mutex_unlock(&dev->device_lock);
if (rets < 0)
mei_io_cb_free(write_cb);
return rets;
}