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| author | Pavel Begunkov <asml.silence@gmail.com> | 2023-01-04 02:34:02 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-01-04 03:03:28 +0100 |
| commit | 9ffa13ff78a0a55df968a72d6f0ebffccee5c9f4 (patch) | |
| tree | 3576e12a99775bf257075621191860613552fd4b /io_uring | |
| parent | io_uring/io-wq: free worker if task_work creation is canceled (diff) | |
| download | linux-9ffa13ff78a0a55df968a72d6f0ebffccee5c9f4.tar.xz linux-9ffa13ff78a0a55df968a72d6f0ebffccee5c9f4.zip | |
io_uring: pin context while queueing deferred tw
Unlike normal tw, nothing prevents deferred tw to be executed right
after an tw item added to ->work_llist in io_req_local_work_add(). For
instance, the waiting task may get waken up by CQ posting or a normal
tw. Thus we need to pin the ring for the rest of io_req_local_work_add()
Cc: stable@vger.kernel.org
Fixes: c0e0d6ba25f18 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1a79362b9c10b8523ef70b061d96523650a23344.1672795998.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 58ac13b69dc8..6bed44855679 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1236,13 +1236,18 @@ static void io_req_local_work_add(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; - if (!llist_add(&req->io_task_work.node, &ctx->work_llist)) + percpu_ref_get(&ctx->refs); + + if (!llist_add(&req->io_task_work.node, &ctx->work_llist)) { + percpu_ref_put(&ctx->refs); return; + } /* need it for the following io_cqring_wake() */ smp_mb__after_atomic(); if (unlikely(atomic_read(&req->task->io_uring->in_idle))) { io_move_task_work_from_local(ctx); + percpu_ref_put(&ctx->refs); return; } @@ -1252,6 +1257,7 @@ static void io_req_local_work_add(struct io_kiocb *req) if (ctx->has_evfd) io_eventfd_signal(ctx); __io_cqring_wake(ctx); + percpu_ref_put(&ctx->refs); } void __io_req_task_work_add(struct io_kiocb *req, bool allow_local) |