[PATCH 5.10 07/54] io_uring: account io_uring internal files as REQ_F_INFLIGHT

Greg Kroah-Hartman
2021-02-11T15:45:27Z

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit 02a13674fa0e8dd326de8b9f4514b41b03d99003 ]

We need to actively cancel anything that introduces a potential circular
loop, where io_uring holds a reference to itself. If the file in question
is an io_uring file, then add the request to the inflight list.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/io_uring.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1000,6 +1000,9 @@ static inline void io_clean_op(struct io
static inline bool __io_match_files(struct io_kiocb *req,
struct files_struct *files)
{
+ if (req->file && req->file->f_op == &io_uring_fops)
+ return true;
+
return ((req->flags & REQ_F_WORK_INITIALIZED) &&
(req->work.flags & IO_WQ_WORK_FILES)) &&
req->work.identity->files == files;
@@ -1398,11 +1401,14 @@ static bool io_grab_identity(struct io_k
return false;
atomic_inc(&id->files->count);
get_nsproxy(id->nsproxy);
- req->flags |= REQ_F_INFLIGHT;

- spin_lock_irq(&ctx->inflight_lock);
- list_add(&req->inflight_entry, &ctx->inflight_list);
- spin_unlock_irq(&ctx->inflight_lock);
+ if (!(req->flags & REQ_F_INFLIGHT)) {
+ req->flags |= REQ_F_INFLIGHT;
+
+ spin_lock_irq(&ctx->inflight_lock);
+ list_add(&req->inflight_entry, &ctx->inflight_list);
+ spin_unlock_irq(&ctx->inflight_lock);
+ }
req->work.flags |= IO_WQ_WORK_FILES;
}
if (!(req->work.flags & IO_WQ_WORK_MM) &&
@@ -5886,8 +5892,10 @@ static void io_req_drop_files(struct io_
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;

- put_files_struct(req->work.identity->files);
- put_nsproxy(req->work.identity->nsproxy);
+ if (req->work.flags & IO_WQ_WORK_FILES) {
+ put_files_struct(req->work.identity->files);
+ put_nsproxy(req->work.identity->nsproxy);
+ }
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
@@ -6159,6 +6167,15 @@ static struct file *io_file_get(struct i
file = __io_file_get(state, fd);
}

+ if (file && file->f_op == &io_uring_fops) {
+ io_req_init_async(req);
+ req->flags |= REQ_F_INFLIGHT;
+
+ spin_lock_irq(&ctx->inflight_lock);
+ list_add(&req->inflight_entry, &ctx->inflight_list);
+ spin_unlock_irq(&ctx->inflight_lock);
+ }
+
return file;
}

@@ -8578,8 +8595,7 @@ static void io_uring_cancel_files(struct

spin_lock_irq(&ctx->inflight_lock);
list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
- if (req->task != task ||
- req->work.identity->files != files)
+ if (!io_match_task(req, task, files))
continue;
found = true;
break;