From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Liu Shixin <liushixin2@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
William Kucharski <william.kucharski@oracle.com>,
Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 5.15 v4] mm/filemap: fix UAF in find_lock_entries
Date: Thu, 7 Jul 2022 20:04:04 +0200 [thread overview]
Message-ID: <YscgFKW4tNbl2V5D@kroah.com> (raw)
In-Reply-To: <YsZOafRSNZWY0EpM@casper.infradead.org>
On Thu, Jul 07, 2022 at 04:09:29AM +0100, Matthew Wilcox wrote:
> On Thu, Jul 07, 2022 at 10:09:38AM +0800, Liu Shixin wrote:
> > Release refcount after xas_set to fix UAF which may cause panic like this:
> >
> > page:ffffea000491fa40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1247e9
> > head:ffffea000491fa00 order:3 compound_mapcount:0 compound_pincount:0
> > memcg:ffff888104f91091
> > flags: 0x2fffff80010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
> > ...
> > page dumped because: VM_BUG_ON_PAGE(PageTail(page))
> > ------------[ cut here ]------------
> > kernel BUG at include/linux/page-flags.h:632!
> > invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
> > CPU: 1 PID: 7642 Comm: sh Not tainted 5.15.51-dirty #26
> > ...
> > Call Trace:
> > <TASK>
> > __invalidate_mapping_pages+0xe7/0x540
> > drop_pagecache_sb+0x159/0x320
> > iterate_supers+0x120/0x240
> > drop_caches_sysctl_handler+0xaa/0xe0
> > proc_sys_call_handler+0x2b4/0x480
> > new_sync_write+0x3d6/0x5c0
> > vfs_write+0x446/0x7a0
> > ksys_write+0x105/0x210
> > do_syscall_64+0x35/0x80
> > entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x7f52b5733130
> > ...
> >
> > This problem has been fixed on mainline by patch 6b24ca4a1a8d ("mm: Use
> > multi-index entries in the page cache") since it deletes the related code.
> >
> > Fixes: 5c211ba29deb ("mm: add and use find_lock_entries")
> > Signed-off-by: Liu Shixin <liushixin2@huawei.com>
>
> Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Now queued up, thanks.
greg k-h
prev parent reply other threads:[~2022-07-07 18:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-07 2:09 [PATCH 5.15 v4] mm/filemap: fix UAF in find_lock_entries Liu Shixin
2022-07-07 3:09 ` Matthew Wilcox
2022-07-07 18:04 ` Greg Kroah-Hartman [this message]
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