From: Jason Gunthorpe Date: Wed, 8 Jan 2020 17:22:03 +0000 (+0200) Subject: RDMA/core: Fix locking in ib_uverbs_event_read X-Git-Tag: Ubuntu-4.15.0-92.93~44 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=bd0b0a07181750572d7dc31f6b1f1f8276edd22d;p=mirror_ubuntu-bionic-kernel.git RDMA/core: Fix locking in ib_uverbs_event_read BugLink: https://bugs.launchpad.net/bugs/1867194 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 Reviewed-by: Håkon Bugge Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Khalid Elmously --- diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c index 236537b6d326..ccb962cca691 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -260,7 +260,6 @@ void ib_uverbs_release_file(struct kref *ref) } 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) @@ -278,19 +277,16 @@ static ssize_t ib_uverbs_event_read(struct ib_uverbs_event_queue *ev_queue, 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); @@ -325,8 +321,7 @@ static ssize_t ib_uverbs_async_event_read(struct file *filp, char __user *buf, { 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)); } @@ -336,9 +331,8 @@ static ssize_t ib_uverbs_comp_event_read(struct file *filp, char __user *buf, 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_file.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)); } @@ -361,7 +355,9 @@ static unsigned int ib_uverbs_event_poll(struct ib_uverbs_event_queue *ev_queue, static unsigned int 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 unsigned int ib_uverbs_comp_event_poll(struct file *filp, @@ -375,9 +371,9 @@ static unsigned int ib_uverbs_comp_event_poll(struct file *filp, 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)