Commit b2bd1cf9 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix racy overflow count reporting 



All ->cq_overflow modifications should be under completion_lock,
otherwise it can report a wrong number to the userspace. Fix it in
io_uring_cancel_files().

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 81b68a5c

fs/io_uring.c

+1 −2
Original line number Diff line number Diff line
@@ -7847,10 +7847,9 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx, 
				clear_bit(0, &ctx->cq_check_overflow);

				ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;

			}

			spin_unlock_irq(&ctx->completion_lock);



			WRITE_ONCE(ctx->rings->cq_overflow,

				atomic_inc_return(&ctx->cached_cq_overflow));

			spin_unlock_irq(&ctx->completion_lock);



			/*

			 * Put inflight ref and overflow ref. If that's

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