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Shutemov" , Matthew Wilcox , David Hildenbrand , Johannes Weiner , Baolin Wang , Barry Song , Kefeng Wang , Ryan Roberts , Nhat Pham , Shakeel Butt , linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 2B26F4000B X-Stat-Signature: 41pph7ksp6dudqwuo1iqu7pasq49wz64 X-HE-Tag: 1731538640-226521 X-HE-Meta: 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 y6rEYonD Gx+DJPtDxv0OWbqWg/UPcJ6ZOhC0UFE7pLw7KaSb7ykRx79H8GCMeUhjPZiIaLvKVNfjE0wS2lQXmdYdJ0zDxMmpI5ogVgkXqsZ0uHMRwl38Msf6W57s0qep31lspXT2rPwhWrBXXtykgugHN/HDi89VxcDX7NGnTUaWUMfozYUjSwp4ptXSuvDuMfqTdU2W9/LOpm7WrX0tA1xplDQ76PRnLydRXVI/x7pVDdLFHisOZy6OyPiU6IEFW+OmZb1lvDZKRTJ/37i7uuR2dJB9RGOd9Bq1k/OTkOumJRDiY10Y8vQisGvVKA9uOXm7cLgsZ99Fn20eMNML2oYPIMosgMpY+r8aBlhrtwVJFn1+wSoLKepRnKYNmn07GyigF/LxXIR1l3WoPuCfH6cz2NLaUmU38+60M9hlpx8JmWp+g6z0aS3fP9wnFxGWiBsEfglzbtumw X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Hugh, LGTM. Acked-by: Chris Li Chris On Sun, Nov 10, 2024 at 1:11=E2=80=AFPM Hugh Dickins wro= te: > > Though even more elusive than before, list_del corruption has still been > seen on THP's deferred split queue. > > The idea in commit e66f3185fa04 was right, but its implementation wrong. > The context omitted an important comment just before the critical test: > "split_folio() removes folio from list on success." In ignoring that > comment, when a THP split succeeded, the code went on to release the > preceding safe folio, preserving instead an irrelevant (formerly head) > folio: which gives no safety because it's not on the list. Fix the logic. > > Fixes: e66f3185fa04 ("mm/thp: fix deferred split queue not partially_mapp= ed") > Signed-off-by: Hugh Dickins > --- > mm/huge_memory.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 03fd4bc39ea1..5734d5d5060f 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3790,7 +3790,9 @@ static unsigned long deferred_split_scan(struct shr= inker *shrink, > * in the case it was underused, then consider it used an= d > * don't add it back to split_queue. > */ > - if (!did_split && !folio_test_partially_mapped(folio)) { > + if (did_split) { > + ; /* folio already removed from list */ > + } else if (!folio_test_partially_mapped(folio)) { > list_del_init(&folio->_deferred_list); > removed++; > } else { > -- > 2.35.3