From: Zhouyi Zhou <zhouzhouyi@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Chris Clayton <chris2553@googlemail.com>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
Miaohe Lin <linmiaohe@huawei.com>,
Boqun Feng <boqun.feng@gmail.com>,
paulmck@kernel.org, linux-kernel <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org, Chris Rankin <rankincj@gmail.com>,
Josh Triplett <josh@joshtriplett.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
rcu <rcu@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
"Huang, Ying" <ying.huang@intel.com>,
Greg KH <gregkh@linuxfoundation.org>
Subject: Re: linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359
Date: Fri, 23 Jul 2021 01:44:24 +0800 [thread overview]
Message-ID: <CAABZP2x_opmE2vh8GRweNvCqogFjJ09UcNq-8t6qZDMsGNY9vA@mail.gmail.com> (raw)
In-Reply-To: <YPlmMnZKgkcLderp@casper.infradead.org>
I apologize sincerely for my irresponsible and hasty email.
I reverted the unnecessary backport of 2799e77529c2 and 2efa33fc7f6e,
tested on the same qemu box as before with the same C program, there
is no warning about RCU this time. dmesg only shows the backtrace of
OOM kill.
As for memory OOMs caused by grace period's undue ends, I found each
deletion of a inode will cause a leak.
1035 void security_inode_free(struct inode *inode)
1036 {
1037 integrity_inode_free(inode);
1038 call_void_hook(inode_free_security, inode);
1039 /*
1040 * The inode may still be referenced in a path walk and
1041 * a call to security_inode_permission() can be made
1042 * after inode_free_security() is called. Ideally, the VFS
1043 * wouldn't do this, but fixing that is a much harder
1044 * job. For now, simply free the i_security via RCU, and
1045 * leave the current inode->i_security pointer intact.
1046 * The inode will be freed after the RCU grace period too.
1047 */
1048 if (inode->i_security)
1049 call_rcu((struct rcu_head *)inode->i_security,
1050 inode_free_by_rcu);
1051 }
I am willing to do any experiment if there is a need.
Sorry again
Best Wishes
Zhouyi
On Thu, Jul 22, 2021 at 8:36 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Jul 22, 2021 at 04:57:57PM +0800, Zhouyi Zhou wrote:
> > Thanks for reviewing,
> >
> > What I have deduced from the dmesg is:
> > In function do_swap_page,
> > after invoking
> > 3385 si = get_swap_device(entry); /* rcu_read_lock */
> > and before
> > 3561 out:
> > 3562 if (si)
> > 3563 put_swap_device(si);
> > The thread got scheduled out in
> > 3454 locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags);
> >
> > I am only familiar with Linux RCU subsystem, hope mm people can solve our
> > confusions.
>
> I don't understamd why you're still talking. The problem is understood.
> You need to revert the unnecessary backport of 2799e77529c2 and
> 2efa33fc7f6e
next prev parent reply other threads:[~2021-07-22 17:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c9fd1311-662c-f993-c8ef-54af036f2f78@googlemail.com>
2021-07-18 21:01 ` linux-5.13.2: warning from kernel/rcu/tree_plugin.h:359 Oleksandr Natalenko
2021-07-18 21:03 ` Oleksandr Natalenko
2021-07-18 21:22 ` Matthew Wilcox
2021-07-18 21:36 ` Chris Clayton
2021-07-18 21:59 ` Paul E. McKenney
2021-07-18 22:51 ` Matthew Wilcox
2021-07-19 1:53 ` Paul E. McKenney
2021-07-19 2:24 ` Zhouyi Zhou
2021-07-19 2:27 ` Zhouyi Zhou
2021-07-19 2:43 ` Matthew Wilcox
2021-07-19 2:59 ` Zhouyi Zhou
2021-07-19 10:14 ` Boqun Feng
2021-07-19 11:12 ` Miaohe Lin
2021-07-19 11:17 ` Oleksandr Natalenko
2021-07-19 11:22 ` Matthew Wilcox
2021-07-19 11:50 ` Miaohe Lin
2021-07-19 11:59 ` Oleksandr Natalenko
2021-07-19 12:08 ` Miaohe Lin
2021-07-19 12:12 ` Oleksandr Natalenko
2021-07-19 12:16 ` Matthew Wilcox
2021-07-19 12:23 ` Oleksandr Natalenko
2021-07-19 16:47 ` Zhouyi Zhou
[not found] ` <CAABZP2yh3J8+P=3PLZVaC47ymKC7PcfQCBBxjXJ9Ybn+HREbdg@mail.gmail.com>
2021-07-22 7:30 ` Chris Clayton
2021-07-22 8:57 ` Zhouyi Zhou
2021-07-22 12:36 ` Matthew Wilcox
2021-07-22 13:26 ` Greg KH
2021-07-22 14:00 ` Greg KH
2021-07-23 1:51 ` Miaohe Lin
2021-07-23 7:02 ` Greg KH
2021-07-23 7:13 ` Miaohe Lin
2021-07-22 17:44 ` Zhouyi Zhou [this message]
2021-07-22 14:05 ` Paul E. McKenney
2021-07-19 12:17 ` Miaohe Lin
2021-07-19 7:32 ` Chris Clayton
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