6.14-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
commit f446c6311e86618a1f81eb576b56a6266307238f upstream.
For older/32-bit systems with highmem, don't assume that the pages in a mapped region are always going to be mapped. If io_region_init_ptr() finds that the pages are coalescable, also check if the first page is a HighMem page or not. If it is, fall through to the usual vmap() mapping rather than attempt to get the unmapped page address.
Cc: stable@vger.kernel.org Fixes: c4d0ac1c1567 ("io_uring/memmap: optimise single folio regions") Link: https://lore.kernel.org/all/681fe2fb.050a0220.f2294.001a.GAE@google.com/ Reported-by: syzbot+5b8c4abafcb1d791ccfc@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/681fed0a.050a0220.f2294.001c.GAE@google.com/ Reported-by: syzbot+6456a99dfdc2e78c4feb@syzkaller.appspotmail.com Tested-by: syzbot+6456a99dfdc2e78c4feb@syzkaller.appspotmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/memmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/io_uring/memmap.c b/io_uring/memmap.c index 76fcc79656b0..07f8a5cbd37e 100644 --- a/io_uring/memmap.c +++ b/io_uring/memmap.c @@ -116,7 +116,7 @@ static int io_region_init_ptr(struct io_mapped_region *mr) void *ptr;
if (io_check_coalesce_buffer(mr->pages, mr->nr_pages, &ifd)) { - if (ifd.nr_folios == 1) { + if (ifd.nr_folios == 1 && !PageHighMem(mr->pages[0])) { mr->ptr = page_address(mr->pages[0]); return 0; }