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Subject[PATCH 3/3] io_uring: Fix remove irrelevant req from the task_list
Date
If the process 0 has been initialized io_uring is complete, and
then fork process 1. If process 1 exits and it leads to delete
all reqs from the task_list. If we kill process 0. We will not
send SIGINT signal to the kworker. So we can not remove the req
from the task_list. The io_sq_wq_submit_work() can do that for
us.

Fixes: 1c4404efcf2c ("io_uring: make sure async workqueue is canceled on exit")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
fs/io_uring.c | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index adaafe857b074..2b95be09c0dad 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2277,13 +2277,11 @@ static void io_sq_wq_submit_work(struct work_struct *work)
break;
cond_resched();
} while (1);
-end_req:
- if (!list_empty(&req->task_list)) {
- spin_lock_irq(&ctx->task_lock);
- list_del_init(&req->task_list);
- spin_unlock_irq(&ctx->task_lock);
- }
}
+end_req:
+ spin_lock_irq(&ctx->task_lock);
+ list_del_init(&req->task_list);
+ spin_unlock_irq(&ctx->task_lock);

/* drop submission reference */
io_put_req(req);
@@ -3716,15 +3714,16 @@ static int io_uring_fasync(int fd, struct file *file, int on)
static void io_cancel_async_work(struct io_ring_ctx *ctx,
struct files_struct *files)
{
+ struct io_kiocb *req;
+
if (list_empty(&ctx->task_list))
return;

spin_lock_irq(&ctx->task_lock);
- while (!list_empty(&ctx->task_list)) {
- struct io_kiocb *req;

- req = list_first_entry(&ctx->task_list, struct io_kiocb, task_list);
- list_del_init(&req->task_list);
+ list_for_each_entry(req, &ctx->task_list, task_list) {
+ if (files && req->files != files)
+ continue;

/*
* The below executes an smp_mb(), which matches with the
@@ -3734,7 +3733,7 @@ static void io_cancel_async_work(struct io_ring_ctx *ctx,
*/
smp_store_mb(req->flags, req->flags | REQ_F_CANCEL); /* B */

- if (req->work_task && (!files || req->files == files))
+ if (req->work_task)
send_sig(SIGINT, req->work_task, 1);
}
spin_unlock_irq(&ctx->task_lock);
--
2.11.0
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