diff options
| author | Jens Axboe <axboe@kernel.dk> | 2025-05-12 09:06:06 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-05-12 09:27:41 -0600 |
| commit | f446c6311e86618a1f81eb576b56a6266307238f (patch) | |
| tree | 0a3c08bb1ad78adaaafc9f377204e2eae1a6d7d9 | |
| parent | 63166b815dc163b2e46426cecf707dc5923d6d13 (diff) | |
io_uring/memmap: don't use page_address() on a highmem page
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>
| -rw-r--r-- | io_uring/memmap.c | 2 |
1 files changed, 1 insertions, 1 deletions
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; } |