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From: Muchun Song In-Reply-To: Date: Fri, 22 Mar 2024 11:24:10 +0800 Cc: syzbot , David Hildenbrand , Matthew Wilcox , Andrew Morton , LKML , Linux-MM , syzkaller-bugs@googlegroups.com Content-Transfer-Encoding: quoted-printable Message-Id: <1349A15A-341F-4EE4-AD40-805A97A9FFD1@linux.dev> References: <0000000000006cfe98061423cde7@google.com> <812E97E8-668F-414D-9480-1D284834A034@linux.dev> To: Oscar Salvador X-Migadu-Flow: FLOW_OUT X-Stat-Signature: omkf1b931kup77eufzshnbafjjz9f4ka X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: B71FCA000D X-Rspam-User: X-HE-Tag: 1711077896-589360 X-HE-Meta: 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 hzpRt41j pj5tPNh0UhR72waRZak3tDR7W2w/U0W87dSrNDLQ++xVVK30pRy++LOG7fQLV+RC5No96Wg5XDZ6v+Rvri7qPyQxYXJyhpf/hpj0LkF67/+eBH88zJpmgMjSw2IjweniB55lm7wZ50g32dG3sULzno2AbQu6BoTdK+oBd172N0hwB51c41eQ3YYyRCF4W6GvogBTGb6sN/VKYhw/OpckPZrk38NeK6d3cQdnawA7/EFlbjx9kPYNQsqSTR29AcDsKSC4JovxtMqTCvua6fcemhxcnq8vLo9qNPgBqRFp2KwIuZFW81hGaurwqj4IIy3GbU8X/DGyhwJKkNKTXYeffQLwvQ4gZB1A0VJK/HY5tSliEI0xDVvccekVMYOKfDZiAI8ZrtPEQA4qMCts3nZToLkwbgwqVtCSxURBdnpKeum9trOo= 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 Mar 21, 2024, at 18:20, Oscar Salvador wrote: >=20 > On Thu, Mar 21, 2024 at 05:49:49PM +0800, Muchun Song wrote: >> There are some more page dumping information from console: >>=20 >> [ 61.367144][ T42] page: refcount:0 mapcount:0 = mapping:0000000000000000 index:0xffff888028132880 pfn:0x28130 >> [ 61.371430][ T42] flags: = 0xfff80000000000(node=3D0|zone=3D1|lastcpupid=3D0xfff) >> [ 61.374455][ T42] page_type: 0xffffffff() >> [ 61.376096][ T42] raw: 00fff80000000000 ffff888015ecd540 = dead000000000100 0000000000000000 >> [ 61.379994][ T42] raw: ffff888028132880 0000000000190000 = 00000000ffffffff 0000000000000000 >>=20 >> Alright, the page is freed (with a refcount of 0). >=20 > Yes, basically the page changed betwen folio_test_large() (returned = true > for PG_Head) and the call to const_folio_flags() (which now returned > false for PG_Head). >=20 > As David pointed out, Willy is working on making PageHutelb more > robust [1]. >=20 >=20 > [1] = https://lore.kernel.org/linux-mm/20240314012506.1600378-1-willy@infradead.= org/ Sorry, I am not on the CC list, so I didn't know this. But thank you and David for this information, I think it could fix this problem. Muchun, Thanks.