io_uring/kbuf: defer release of mapped buffer rings
commit c392cbec upstream. 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: c56e022c ("io_uring: add support for user mapped provided buffer ring") Reported-by:Jann Horn <jannh@google.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
4ca5f54a
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