From c392cbecd8eca4c53f2bf508731257d9d0a21c2d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 27 Nov 2023 16:47:04 -0700 Subject: io_uring/kbuf: defer release of mapped buffer rings If a provided buffer ring is setup with IOU_PBUF_RING_MMAP, then the kernel allocates the memory for it and the application is expected to mmap(2) this memory. However, io_uring uses remap_pfn_range() for this operation, so we cannot rely on normal munmap/release on freeing them for us. Stash an io_buf_free entry away for each of these, if any, and provide a helper to free them post ->release(). Cc: stable@vger.kernel.org Fixes: c56e022c0a27 ("io_uring: add support for user mapped provided buffer ring") Reported-by: Jann Horn Signed-off-by: Jens Axboe --- include/linux/io_uring_types.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index d3009d56af0b..805bb635cdf5 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -340,6 +340,9 @@ struct io_ring_ctx { struct list_head io_buffers_cache; + /* deferred free list, protected by ->uring_lock */ + struct hlist_head io_buf_list; + /* Keep this last, we don't need it for the fast path */ struct wait_queue_head poll_wq; struct io_restriction restrictions; -- cgit v1.2.3