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Received: from 30.74.113.73(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0XCMHsUt_1791446336 cluster:ay36) by smtp.aliyun-inc.com; Thu, 08 Oct 2026 15:58:57 +0800 Message-ID: <6aa5a165-3ba6-4974-b549-fed7318ead49@linux.alibaba.com> Date: Thu, 8 Oct 2026 15:58:56 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] shmem: FALLOC_FL_PUNCH_HOLE vs fault-around race corrupts page cache / rss counters To: Ayush Ranjan , Pedro Falcato Cc: Hugh Dickins , Matthew Wilcox , Andrew Morton , Jan Kara , David Hildenbrand , Gregory Price , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260924061708.1645968-1-ayushr@modal.com> <20260925053027.1998394-1-ayushr@modal.com> <20260925065013.3682431-1-ayushr@modal.com> <20261003033107.1488699-1-ayushr@modal.com> From: Baolin Wang In-Reply-To: <20261003033107.1488699-1-ayushr@modal.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: DA749100007 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 1bp9m1rrwiqmt55dzd4111uj8s9of9uw X-HE-Tag: 1791446341-182711 X-HE-Meta: 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 OM4Th37z YtDtzAbGjfhnxIEy5+NsTkTBOANxrDyVDPSxmGFDLJCTucR76RO86IJswPAvP5iXdXddz6mhEEMhahj9zfTK0IgeMEL0t3qlA5Xd1/vZFV9aVzFhkz2dmcsEX19rbkor9pKHIeyPQYtspvIraFsbTAyKJWV+JmEU/I1Yh0KatCwESGbQFOBShketxY74Kkes8vURa4G5ZgK0Fp+fPqiRNbv57aM6Bg3OyQqm71aX2y7IGNxah8J33pNQPBMb+OJWoL+CLLu4z63d9eXC2jbuc56cjRXDUqUkJx/9JGz9OQ0HgyG+pwQ2MuzicH1W+AGI9a7ZyjGLVQlTYygcP8Dj1RvF4VsbnBJ3M6AuWMQVrMHOF2es= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/3/26 11:31 AM, Ayush Ranjan wrote: > Hi all, > > Gentle ping on this. Sorry for the late reply due to my vacation. The reproducer in my previous mail [1] triggers > "Bad page cache ... still mapped when deleted" on 6.18.46 within a > couple of minutes on a 128-CPU bare-metal box, with no fork() and no > gVisor involved. > > We continue to hit this in production at low frequency, so I am happy > to test patches or collect more data if that would help. Now I can reproduce this issue on my machine with the latest mm-unstable branch, and I understand the race. I have confirmed that Andrew's patch can fix it. You can try Andrew's patch.