From 27122c079f5b4b4ecf1323b65700edc57e07bf6e Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 7 Sep 2023 13:50:08 +0100 Subject: io_uring: fix unprotected iopoll overflow [ 71.490669] WARNING: CPU: 3 PID: 17070 at io_uring/io_uring.c:769 io_cqring_event_overflow+0x47b/0x6b0 [ 71.498381] Call Trace: [ 71.498590] [ 71.501858] io_req_cqe_overflow+0x105/0x1e0 [ 71.502194] __io_submit_flush_completions+0x9f9/0x1090 [ 71.503537] io_submit_sqes+0xebd/0x1f00 [ 71.503879] __do_sys_io_uring_enter+0x8c5/0x2380 [ 71.507360] do_syscall_64+0x39/0x80 We decoupled CQ locking from ->task_complete but haven't fixed up places forcing locking for CQ overflows. Fixes: ec26c225f06f5 ("io_uring: merge iopoll and normal completion paths") Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'io_uring') diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 58d8dd34a45ff..090913acf1db4 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -908,7 +908,7 @@ static void __io_flush_post_cqes(struct io_ring_ctx *ctx) struct io_uring_cqe *cqe = &ctx->completion_cqes[i]; if (!io_fill_cqe_aux(ctx, cqe->user_data, cqe->res, cqe->flags)) { - if (ctx->task_complete) { + if (ctx->lockless_cq) { spin_lock(&ctx->completion_lock); io_cqring_event_overflow(ctx, cqe->user_data, cqe->res, cqe->flags, 0, 0); @@ -1566,7 +1566,7 @@ void __io_submit_flush_completions(struct io_ring_ctx *ctx) if (!(req->flags & REQ_F_CQE_SKIP) && unlikely(!io_fill_cqe_req(ctx, req))) { - if (ctx->task_complete) { + if (ctx->lockless_cq) { spin_lock(&ctx->completion_lock); io_req_cqe_overflow(req); spin_unlock(&ctx->completion_lock); -- cgit 1.2.3-korg