From: Greg KH <gregkh@linuxfoundation.org>
To: mawupeng <mawupeng1@huawei.com>
Cc: rppt@linux.vnet.ibm.com, hughd@google.com, aarcange@redhat.com,
hannes@cmpxchg.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com,
willy@infradead.org
Subject: Re: [PATCH stable 4.14,4.19 1/1] mm: Fix page counter mismatch in shmem_mfill_atomic_pte
Date: Tue, 16 Aug 2022 09:15:18 +0200 [thread overview]
Message-ID: <YvtEBv35OUEtDsAj@kroah.com> (raw)
In-Reply-To: <b7468bcc-4b75-1190-5eae-9796d35b048c@huawei.com>
On Tue, Aug 16, 2022 at 03:04:08PM +0800, mawupeng wrote:
>
>
> On 2022/8/16 13:31, Greg KH wrote:
> > On Tue, Aug 16, 2022 at 11:27:08AM +0800, mawupeng wrote:
> >> Cc Greg
> >
> > Cc Greg for what? I have no context here at all as to what you want me
> > to do..
>
> We found a bug related to memory cgroup counter in stable 4.14/4.19.
> shmem_mfill_atomic_pte() wrongly called mem_cgroup_cancel_charge() in "success"
> path, it should mem_cgroup_uncharge() to dec memory counter instead.
> mem_cgroup_cancel_charge() should only be used if this transaction is
> unsuccessful and mem_cgroup_uncharge() is used to do this if this transaction
> succeed.
>
> Commit 3fea5a499d57 ("mm: memcontrol: convert page cache to a new mem_cgroup_charge() API")
> in v5.8-rc1 change is charge/uncharge/cancel logic so don't have this
> problem.
>
> This counter will underflow to negative maximum value and trigger oom to kill all
> process include sshd and leave system unaccessible.
>
> The reason cc you is that we want to merge this bugfix into stable 4.14/4.19.
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
prev parent reply other threads:[~2022-08-16 8:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 1:32 Wupeng Ma
2022-08-16 3:27 ` mawupeng
2022-08-16 5:31 ` Greg KH
2022-08-16 7:04 ` mawupeng
2022-08-16 7:15 ` Greg KH [this message]
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