lkml.org 
[lkml]   [2020]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.4 08/96] RDMA/core: Fix locking in ib_uverbs_event_read
Date
From: Jason Gunthorpe <jgg@mellanox.com>

commit 14e23bd6d22123f6f3b2747701fa6cd4c6d05873 upstream.

This should not be using ib_dev to test for disassociation, during
disassociation is_closed is set under lock and the waitq is triggered.

Instead check is_closed and be sure to re-obtain the lock to test the
value after the wait_event returns.

Fixes: 036b10635739 ("IB/uverbs: Enable device removal when there are active user space applications")
Link: https://lore.kernel.org/r/1578504126-9400-12-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/core/uverbs_main.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)

--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -220,7 +220,6 @@ void ib_uverbs_release_file(struct kref
}

static ssize_t ib_uverbs_event_read(struct ib_uverbs_event_queue *ev_queue,
- struct ib_uverbs_file *uverbs_file,
struct file *filp, char __user *buf,
size_t count, loff_t *pos,
size_t eventsz)
@@ -238,19 +237,16 @@ static ssize_t ib_uverbs_event_read(stru

if (wait_event_interruptible(ev_queue->poll_wait,
(!list_empty(&ev_queue->event_list) ||
- /* The barriers built into wait_event_interruptible()
- * and wake_up() guarentee this will see the null set
- * without using RCU
- */
- !uverbs_file->device->ib_dev)))
+ ev_queue->is_closed)))
return -ERESTARTSYS;

+ spin_lock_irq(&ev_queue->lock);
+
/* If device was disassociated and no event exists set an error */
- if (list_empty(&ev_queue->event_list) &&
- !uverbs_file->device->ib_dev)
+ if (list_empty(&ev_queue->event_list) && ev_queue->is_closed) {
+ spin_unlock_irq(&ev_queue->lock);
return -EIO;
-
- spin_lock_irq(&ev_queue->lock);
+ }
}

event = list_entry(ev_queue->event_list.next, struct ib_uverbs_event, list);
@@ -285,8 +281,7 @@ static ssize_t ib_uverbs_async_event_rea
{
struct ib_uverbs_async_event_file *file = filp->private_data;

- return ib_uverbs_event_read(&file->ev_queue, file->uverbs_file, filp,
- buf, count, pos,
+ return ib_uverbs_event_read(&file->ev_queue, filp, buf, count, pos,
sizeof(struct ib_uverbs_async_event_desc));
}

@@ -296,9 +291,8 @@ static ssize_t ib_uverbs_comp_event_read
struct ib_uverbs_completion_event_file *comp_ev_file =
filp->private_data;

- return ib_uverbs_event_read(&comp_ev_file->ev_queue,
- comp_ev_file->uobj.ufile, filp,
- buf, count, pos,
+ return ib_uverbs_event_read(&comp_ev_file->ev_queue, filp, buf, count,
+ pos,
sizeof(struct ib_uverbs_comp_event_desc));
}

@@ -321,7 +315,9 @@ static __poll_t ib_uverbs_event_poll(str
static __poll_t ib_uverbs_async_event_poll(struct file *filp,
struct poll_table_struct *wait)
{
- return ib_uverbs_event_poll(filp->private_data, filp, wait);
+ struct ib_uverbs_async_event_file *file = filp->private_data;
+
+ return ib_uverbs_event_poll(&file->ev_queue, filp, wait);
}

static __poll_t ib_uverbs_comp_event_poll(struct file *filp,
@@ -335,9 +331,9 @@ static __poll_t ib_uverbs_comp_event_pol

static int ib_uverbs_async_event_fasync(int fd, struct file *filp, int on)
{
- struct ib_uverbs_event_queue *ev_queue = filp->private_data;
+ struct ib_uverbs_async_event_file *file = filp->private_data;

- return fasync_helper(fd, filp, on, &ev_queue->async_queue);
+ return fasync_helper(fd, filp, on, &file->ev_queue.async_queue);
}

static int ib_uverbs_comp_event_fasync(int fd, struct file *filp, int on)

\
 
 \ /
  Last update: 2020-02-13 16:37    [W:0.214 / U:0.204 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site