6.6-stable review patch. If anyone has any objections, please let me know.
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From: Pavel Begunkov asml.silence@gmail.com
Commit 43eef70e7e2ac74e7767731dd806720c7fb5e010 upstream.
io_pages_unmap() is a bit tricky in trying to figure whether the pages were previously vmap'ed or not. In particular If there is juts one page it belives there is no need to vunmap. Paired io_pages_map(), however, could've failed io_mem_alloc_compound() and attempted to io_mem_alloc_single(), which does vmap, and that leads to unpaired vmap.
The solution is to fail if io_mem_alloc_compound() can't allocate a single page. That's the easiest way to deal with it, and those two functions are getting removed soon, so no need to overcomplicate it.
Cc: stable@vger.kernel.org Fixes: 3ab1db3c6039e ("io_uring: get rid of remap_pfn_range() for mapping rings/sqes") Signed-off-by: Pavel Begunkov asml.silence@gmail.com Link: https://lore.kernel.org/r/477e75a3907a2fe83249e49c0a92cd480b2c60e0.173256984... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2889,6 +2889,8 @@ static void *io_pages_map(struct page ** ret = io_mem_alloc_compound(pages, nr_pages, size, gfp); if (!IS_ERR(ret)) goto done; + if (nr_pages == 1) + goto fail;
ret = io_mem_alloc_single(pages, nr_pages, size, gfp); if (!IS_ERR(ret)) { @@ -2897,7 +2899,7 @@ done: *npages = nr_pages; return ret; } - +fail: kvfree(pages); *out_pages = NULL; *npages = 0;