From f6dc5a36195d3f5be769f60d6987150192dfb099 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 25 Nov 2025 12:33:06 +0000 Subject: [PATCH] io_uring: fix mixed cqe overflow handling I started to see zcrx data corruptions. That turned out to be due to CQ tail pointing to a stale entry which happened to be from a zcrx request. I.e. the tail is incremented without the CQE memory being changed. The culprit is __io_cqring_overflow_flush() passing "cqe32=true" to io_get_cqe_overflow() for non-mixed CQE32 setups, which only expects it to be set for mixed 32B CQEs and not for SETUP_CQE32. The fix is slightly hacky, long term it's better to unify mixed and CQE32 handling. Fixes: e26dca67fde19 ("io_uring: add support for IORING_SETUP_CQE_MIXED") Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 296667ba712c..02339b74ba8d 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -634,6 +634,8 @@ static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool dying) is_cqe32 = true; cqe_size <<= 1; } + if (ctx->flags & IORING_SETUP_CQE32) + is_cqe32 = false; if (!dying) { if (!io_get_cqe_overflow(ctx, &cqe, true, is_cqe32)) -- 2.47.3