From: Oscar Salvador <osalvador@suse.de>
To: Muchun Song <muchun.song@linux.dev>
Cc: syzbot <syzbot+3b9148f91b7869120e81@syzkaller.appspotmail.com>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [mm?] kernel BUG in const_folio_flags
Date: Thu, 21 Mar 2024 11:20:00 +0100 [thread overview]
Message-ID: <ZfwJ0JOgcMCTcSgZ@localhost.localdomain> (raw)
In-Reply-To: <812E97E8-668F-414D-9480-1D284834A034@linux.dev>
On Thu, Mar 21, 2024 at 05:49:49PM +0800, Muchun Song wrote:
> There are some more page dumping information from console:
>
> [ 61.367144][ T42] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888028132880 pfn:0x28130
> [ 61.371430][ T42] flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff)
> [ 61.374455][ T42] page_type: 0xffffffff()
> [ 61.376096][ T42] raw: 00fff80000000000 ffff888015ecd540 dead000000000100 0000000000000000
> [ 61.379994][ T42] raw: ffff888028132880 0000000000190000 00000000ffffffff 0000000000000000
>
> Alright, the page is freed (with a refcount of 0).
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).
As David pointed out, Willy is working on making PageHutelb more
robust [1].
[1] https://lore.kernel.org/linux-mm/20240314012506.1600378-1-willy@infradead.org/
--
Oscar Salvador
SUSE Labs
next prev parent reply other threads:[~2024-03-21 10:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 4:04 [syzbot] [mm?] kernel BUG in const_folio_flags syzbot
2024-03-21 9:49 ` Muchun Song
2024-03-21 9:58 ` David Hildenbrand
2024-03-21 10:20 ` Oscar Salvador [this message]
2024-03-22 3:24 ` Muchun Song
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