[PATCH 5.10 06/54] io_uring: fix files cancellation

Greg Kroah-Hartman
2021-02-11T15:41:19Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit bee749b187ac57d1faf00b2ab356ff322230fce8 ]

io_uring_cancel_files()'s task check condition mistakenly got flipped.

1. There can't be a request in the inflight list without
IO_WQ_WORK_FILES, kill this check to keep the whole condition simpler.
2. Also, don't call the function for files==NULL to not do such a check,
all that staff is already handled well by its counter part,
__io_uring_cancel_task_requests().

With that just flip the task check.

Also, it iowq-cancels all request of current task there, don't forget to
set right ->files into struct io_task_cancel.

Fixes: c1973b38bf639 ("io_uring: cancel only requests of current task")
Reported-by: syzbot+c0d52d0b3c0c3ffb9525@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/io_uring.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8571,15 +8571,14 @@ static void io_uring_cancel_files(struct
struct files_struct *files)
{
while (!list_empty_careful(&ctx->inflight_list)) {
- struct io_task_cancel cancel = { .task = task, .files = NULL, };
+ struct io_task_cancel cancel = { .task = task, .files = files };
struct io_kiocb *req;
DEFINE_WAIT(wait);
bool found = false;

spin_lock_irq(&ctx->inflight_lock);
list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
- if (req->task == task &&
- (req->work.flags & IO_WQ_WORK_FILES) &&
+ if (req->task != task ||
req->work.identity->files != files)
continue;
found = true;
@@ -8665,10 +8664,11 @@ static void io_uring_cancel_task_request

io_cancel_defer_files(ctx, task, files);
io_cqring_overflow_flush(ctx, true, task, files);
- io_uring_cancel_files(ctx, task, files);

if (!files)
__io_uring_cancel_task_requests(ctx, task);
+ else
+ io_uring_cancel_files(ctx, task, files);

if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
atomic_dec(&task->io_uring->in_idle);