On 8/10/20 9:36 AM, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 449dc8c9 Merge tag 'for-v5.9' of git://git.kernel.org/pub/..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14d41e02900000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9d25235bf0162fbc
> dashboard link: https://syzkaller.appspot.com/bug?extid=996f91b6ec3812c48042
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/
> c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133c9006900000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1191cb1a900000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
Thanks, the below should fix this one.
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 443eecdfeda9..f9be665d1c5e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -898,6 +898,7 @@ static void io_put_req(struct io_kiocb *req);
static void io_double_put_req(struct io_kiocb *req);
static void __io_double_put_req(struct io_kiocb *req);
static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
+static void __io_queue_linked_timeout(struct io_kiocb *req);
static void io_queue_linked_timeout(struct io_kiocb *req);
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_files_update *ip,
@@ -1179,7 +1180,7 @@ static void io_prep_async_link(struct io_kiocb *req)
io_prep_async_work(cur);
}
-static void __io_queue_async_work(struct io_kiocb *req)
+static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *link = io_prep_linked_timeout(req);
@@ -1187,16 +1188,19 @@ static void __io_queue_async_work(struct io_kiocb *req)
trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
&req->work, req->flags);
io_wq_enqueue(ctx->io_wq, &req->work);
-
- if (link)
- io_queue_linked_timeout(link);
+ return link;
}
static void io_queue_async_work(struct io_kiocb *req)
{
+ struct io_kiocb *link;
+
/* init ->work of the whole link before punting */
io_prep_async_link(req);
- __io_queue_async_work(req);
+ link = __io_queue_async_work(req);
+
+ if (link)
+ io_queue_linked_timeout(link);
}
static void io_kill_timeout(struct io_kiocb *req)
@@ -1229,12 +1233,19 @@ static void __io_queue_deferred(struct io_ring_ctx *ctx)
do {
struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
struct io_defer_entry, list);
+ struct io_kiocb *link;
if (req_need_defer(de->req, de->seq))
break;
list_del_init(&de->list);
/* punt-init is done before queueing for defer */
- __io_queue_async_work(de->req);
+ link = __io_queue_async_work(de->req);
+ if (link) {
+ __io_queue_linked_timeout(link);
+ /* drop submission reference */
+ link->flags |= REQ_F_COMP_LOCKED;
+ io_put_req(link);
+ }
kfree(de);
} while (!list_empty(&ctx->defer_list));
}
@@ -5945,15 +5956,12 @@ static enum hrtimer_restart io_link_timeout_fn(struct
hrtimer *timer)
return HRTIMER_NORESTART;
}
-static void io_queue_linked_timeout(struct io_kiocb *req)
+static void __io_queue_linked_timeout(struct io_kiocb *req)
{
- struct io_ring_ctx *ctx = req->ctx;
-
/*
* If the list is now empty, then our linked request finished before
* we got a chance to setup the timer
*/
- spin_lock_irq(&ctx->completion_lock);
if (!list_empty(&req->link_list)) {
struct io_timeout_data *data = &req->io->timeout;
@@ -5961,6 +5969,14 @@ static void io_queue_linked_timeout(struct io_kiocb *req)
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
data->mode);
}
+}
+
+static void io_queue_linked_timeout(struct io_kiocb *req)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+
+ spin_lock_irq(&ctx->completion_lock);
+ __io_queue_linked_timeout(req);
spin_unlock_irq(&ctx->completion_lock);
/* drop submission reference */
--
Jens Axboe
