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charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 793D7C0005 X-Stat-Signature: pyeaiuqjuo3mw4uzj9f48ok4rnxkotct X-Rspam-User: X-HE-Tag: 1753921383-806202 X-HE-Meta: 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 i6nUJpsp knFMaNGFEFNXi9z3XDEltwf2X0Ba0E91XzLBtW9nE+g/omTeHdb5meP6+XJ9TGuZF9DLN3YqBx+8Rg1V976MxkeMAB0McGEb3k7Q19rNqsQsbJfTsRGHqSe3qGe8AeRMDKl0RDqd4bOlxmzbz5Rnhq7QaSR7V0mT63lqu0CvxCG32crAkGMGOgnCNf4nWusDrHz0MujHH3fcoUm10tewJXJvCSXuBw+8znLtbuynUxzIpMuOSOwFN2pn+0eaZeRWREuYI/NNBzuxmy1BgU9CU2AAjmyZOpa+KIs4JPelS8ihL/mo3yxAInx5XYtAPe3sWb/Dq+lVgxrkxuJLoDstWZbKUnJjdwkjfnALo4LnFqZLvxRemI+BJrtn4Pm9PG2PDfiWg4L/uZmZX5JzejNEJXszbX1TABUdi6Z9ib2nsjfFX8O6yQ5pE4jSrhIjXsjLdWG0h 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: On Wed, Jul 30, 2025 at 5:21=E2=80=AFPM Nhat Pham wrote= : > > On Wed, Jul 30, 2025 at 4:41=E2=80=AFPM SeongJae Park wro= te: > > This might not be safe. > > It's conceivable that in zswap_compress(), some compression algorithm > "successfully" compresses a page to the same size (comp_ret =3D=3D 0). We > hand that to zsmalloc, which happily stores the page. > > When we "decompress" the page again, we will attempt to > memcpy_to_folio from a bogus address (the handle from zsmalloc). > > So, in zswap_compress, you have to treat both comp_ret =3D=3D 0 and dlen > =3D=3D PAGE_SIZE as "compression failure". Meant to say comp_ret !=3D 0 here... sorry for the confusion...