From: Naoya Horiguchi naoya.horiguchi@nec.com
commit 4737edbbdd4958ae29ca6a310a6a2fa4e0684b01 upstream.
split_huge_page_to_list() WARNs when called for huge zero pages, which sounds to me too harsh because it does not imply a kernel bug, but just notifies the event to admins. On the other hand, this is considered as critical by syzkaller and makes its testing less efficient, which seems to me harmful.
So replace the VM_WARN_ON_ONCE_FOLIO with pr_warn_ratelimited.
Link: https://lkml.kernel.org/r/20230406082004.2185420-1-naoya.horiguchi@linux.dev Fixes: 478d134e9506 ("mm/huge_memory: do not overkill when splitting huge_zero_page") Signed-off-by: Naoya Horiguchi naoya.horiguchi@nec.com Reported-by: syzbot+07a218429c8d19b1fb25@syzkaller.appspotmail.com Link: https://lore.kernel.org/lkml/000000000000a6f34a05e6efcd01@google.com/ Reviewed-by: Yang Shi shy828301@gmail.com Cc: Miaohe Lin linmiaohe@huawei.com Cc: Tetsuo Handa penguin-kernel@i-love.sakura.ne.jp Cc: Xu Yu xuyu@linux.alibaba.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/huge_memory.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2655,9 +2655,10 @@ int split_huge_page_to_list(struct page VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
is_hzp = is_huge_zero_page(&folio->page); - VM_WARN_ON_ONCE_FOLIO(is_hzp, folio); - if (is_hzp) + if (is_hzp) { + pr_warn_ratelimited("Called split_huge_page for huge zero page\n"); return -EBUSY; + }
if (folio_test_writeback(folio)) return -EBUSY;