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mm/huge_memory.c: warn with pr_warn_ratelimited instead of VM_WARN_ON_ONCE_FOLIO 

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: 478d134e95 ("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>
This commit is contained in:
Naoya Horiguchi 2023-04-06 17:20:04 +09:00 committed by Andrew Morton
parent 82f951340f
commit 4737edbbdd
1 changed files with 3 additions and 2 deletions
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5
mm/huge_memory.c
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@ -2665,9 +2665,10 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
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;