From: Tejun Heo <tj@kernel.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>,
Greg Thelen <gthelen@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chinwen Chang <chinwen.chang@mediatek.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
David Rientjes <rientjes@google.com>,
Davidlohr Bueso <dbueso@suse.de>, Ingo Molnar <mingo@redhat.com>,
Jann Horn <jannh@google.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
Michel Lespinasse <walken@google.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Steven Rostedt <rostedt@goodmis.org>,
Vlastimil Babka <vbabka@suse.cz>,
Yafang Shao <laoar.shao@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
dsahern@kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jakub Kicinski <kuba@kernel.org>,
liuhangbin@gmail.com, LKML <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH] mm: mmap_lock: fix use-after-free race and css ref leak in tracepoints
Date: Wed, 2 Dec 2020 18:30:30 -0500 [thread overview]
Message-ID: <X8gjliMAsPYZFrU1@mtj.duckdns.org> (raw)
In-Reply-To: <CALvZod4ZroEOwbiZ5aKTd28d1tva0YLWfLZTF-N-xXd_40rUsA@mail.gmail.com>
Hello,
On Wed, Dec 02, 2020 at 03:23:57PM -0800, Shakeel Butt wrote:
> > There've been some changes to cgroup ids recently and now cgroup id, ino and
> > its file_handle are all compatible. On 64bit ino machines, they're all the
> > same and won't be reused. On 32bit ino machines, the lower 32bit of full id
> > is used as ino. ino may be reused but not the full 64bit id.
>
> __kernfs_new_node() is using idr_alloc_cyclic() which will return
> 32bit ID. If I am understanding this correctly the full ID is
> generated similarly for 32bit and 64bit machines but for 64bit
> machines the whole ID is inode number while on 32bit machines the
> lower 32bits contains the inode number. Is that correct?
Yes, that's correct.
Thanks.
--
tejun
next prev parent reply other threads:[~2020-12-02 23:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 23:35 [PATCH] mm: mmap_lock: fix use-after-free race and css ref leak in tracepoints Axel Rasmussen
2020-12-01 1:33 ` Shakeel Butt
2020-12-01 17:36 ` Axel Rasmussen
2020-12-01 17:56 ` Greg Thelen
2020-12-01 18:42 ` Shakeel Butt
2020-12-01 19:13 ` Axel Rasmussen
2020-12-01 20:53 ` Shakeel Butt
2020-12-02 0:15 ` Axel Rasmussen
2020-12-02 0:36 ` Shakeel Butt
2020-12-02 1:07 ` Steven Rostedt
2020-12-02 1:11 ` Shakeel Butt
2020-12-04 16:36 ` Vlastimil Babka
2020-12-04 17:46 ` Axel Rasmussen
2020-12-02 19:00 ` Tejun Heo
2020-12-02 23:23 ` Shakeel Butt
2020-12-02 23:30 ` Tejun Heo [this message]
2020-12-01 3:57 ` Steven Rostedt
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