Fix the reference counting usage to be handled in the event file creation/destruction function, instead of being done by the caller. This is done for both async/non-async event files.
Based on Jason Gunthorpe report at https://www.mail-archive.com/ linux-rdma@vger.kernel.org/msg24680.html: "The existing code for this is broken, in ib_uverbs_get_context all the error paths between ib_uverbs_alloc_event_file and the kref_get(file->ref) are wrong - this will result in fput() which will call ib_uverbs_event_close, which will try to do kref_put and ib_unregister_event_handler - which are no longer paired." Signed-off-by: Yishai Hadas <yish...@mellanox.com> Signed-off-by: Shachar Raindel <rain...@mellanox.com> --- drivers/infiniband/core/uverbs.h | 1 + drivers/infiniband/core/uverbs_cmd.c | 11 +------- drivers/infiniband/core/uverbs_main.c | 44 ++++++++++++++++++++++++++++---- 3 files changed, 40 insertions(+), 16 deletions(-) diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h index ba365b6..60e6e3d 100644 --- a/drivers/infiniband/core/uverbs.h +++ b/drivers/infiniband/core/uverbs.h @@ -178,6 +178,7 @@ void idr_remove_uobj(struct idr *idp, struct ib_uobject *uobj); struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file, int is_async); +void ib_uverbs_free_async_event_file(struct ib_uverbs_file *uverbs_file); struct ib_uverbs_event_file *ib_uverbs_lookup_comp_file(int fd); void ib_uverbs_release_ucq(struct ib_uverbs_file *file, diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index bbb02ff..5720a92 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -367,16 +367,6 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file, goto err_file; } - file->async_file = filp->private_data; - - INIT_IB_EVENT_HANDLER(&file->event_handler, file->device->ib_dev, - ib_uverbs_event_handler); - ret = ib_register_event_handler(&file->event_handler); - if (ret) - goto err_file; - - kref_get(&file->async_file->ref); - kref_get(&file->ref); file->ucontext = ucontext; fd_install(resp.async_fd, filp); @@ -386,6 +376,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file, return in_len; err_file: + ib_uverbs_free_async_event_file(file); fput(filp); err_fd: diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c index f6eef2d..c238eba 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -406,10 +406,9 @@ static int ib_uverbs_event_close(struct inode *inode, struct file *filp) } spin_unlock_irq(&file->lock); - if (file->is_async) { + if (file->is_async) ib_unregister_event_handler(&file->uverbs_file->event_handler); - kref_put(&file->uverbs_file->ref, ib_uverbs_release_file); - } + kref_put(&file->uverbs_file->ref, ib_uverbs_release_file); kref_put(&file->ref, ib_uverbs_release_event_file); return 0; @@ -541,13 +540,20 @@ void ib_uverbs_event_handler(struct ib_event_handler *handler, NULL, NULL); } +void ib_uverbs_free_async_event_file(struct ib_uverbs_file *file) +{ + kref_put(&file->async_file->ref, ib_uverbs_release_event_file); + file->async_file = NULL; +} + struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file, int is_async) { struct ib_uverbs_event_file *ev_file; struct file *filp; + int ret; - ev_file = kmalloc(sizeof *ev_file, GFP_KERNEL); + ev_file = kzalloc(sizeof(*ev_file), GFP_KERNEL); if (!ev_file) return ERR_PTR(-ENOMEM); @@ -556,15 +562,41 @@ struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file, INIT_LIST_HEAD(&ev_file->event_list); init_waitqueue_head(&ev_file->poll_wait); ev_file->uverbs_file = uverbs_file; + kref_get(&ev_file->uverbs_file->ref); ev_file->async_queue = NULL; - ev_file->is_async = is_async; ev_file->is_closed = 0; filp = anon_inode_getfile("[infinibandevent]", &uverbs_event_fops, ev_file, O_RDONLY); if (IS_ERR(filp)) - kfree(ev_file); + goto err_put_refs; + + if (is_async) { + WARN_ON(uverbs_file->async_file); + uverbs_file->async_file = ev_file; + kref_get(&uverbs_file->async_file->ref); + INIT_IB_EVENT_HANDLER(&uverbs_file->event_handler, + uverbs_file->device->ib_dev, + ib_uverbs_event_handler); + ret = ib_register_event_handler(&uverbs_file->event_handler); + if (ret) + goto err_put_file; + + /* At that point async file stuff was fully set */ + ev_file->is_async = 1; + } + + return filp; + +err_put_file: + fput(filp); + kref_put(&uverbs_file->async_file->ref, ib_uverbs_release_event_file); + uverbs_file->async_file = NULL; + return ERR_PTR(ret); +err_put_refs: + kref_put(&ev_file->uverbs_file->ref, ib_uverbs_release_file); + kref_put(&ev_file->ref, ib_uverbs_release_event_file); return filp; } -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
