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h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=MDxQK3nNi2zbugcG3WV49DwqFKMKaOsn4LPoeJLhocxH+BJdySYoF1E8c98AwqOZo UaNT7rFbmUS9fzyQuaecKztRhAl/06VXVwOn9EEtILXjBGwGiDe9goWeNukYmauBNA VvlUpu5mSXcfuxM3rnL/GiY3i2nwsnfQkB32inUY= Date: Tue, 18 Feb 2025 20:03:55 -0800 From: Andrew Morton To: Barry Song <21cnbao@gmail.com> Cc: gaoxu , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Suren Baghdasaryan , Yosry Ahmed Subject: Re: [PATCH v4] mm: Fix possible NULL pointer dereference in __swap_duplicate Message-Id: <20250218200355.959a79bf9b6253772a95e782@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 2FEDC140002 X-Stat-Signature: noift7zfyg65fey1zdxgn5f3933icrbh X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1739937838-669275 X-HE-Meta: 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 WaxhMDeN UG/0/MqQZO5ZWLnO2ESwHosmIPbKSF6l6F6EEO22OPbU3Mva+RDB56na6A+oSa4hsockGRMbedUDrYJ9AMSBm5st9p/Fr8TuGbyGTC+rHjQ4UkUspbO/o1zgxpHv5FboIfyTpTVlQtD4uMaMwOZvAUqYdS3mT3xdCdGr1JIBK5sDoGzePHdDWvRIWTytfkQylrAtW5Xym2jqPedYsTicFTpwFBRsaj2rs6Fo8kYjIS/Lfke11KeTzYZErcgrHE45a1OTAeKVrzpuOWc3kX+QL+fMXKHqa3KUDpDDCHcWyd/GkIzz3mW3QM1nHLjWOJyEYg32DYCeGhFd2kfndcXgZByP2I2O15HqRvXakV3TV6hPs0lgsZLvIVUGPKzSWVrBau8oBPfuu5l3nUeNLRhvVqnn0Z0xOVPQTUGq+ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 19 Feb 2025 15:28:26 +1300 Barry Song <21cnbao@gmail.com> wrote: > > The patch seems to only provide a workaround, but there are no more > > effective software solutions to handle the bit flips problem. This path > > will change the issue from a system crash to a process exception, thereby > > reducing the impact on the entire machine. > > > > Signed-off-by: gao xu > > Regardless of whether the above statement is 100% accurate or whether > a bit-flip actually exists, providing this check still seems useful, > at least for > defensive programming. I'm doubtful as well. How often has this crash been observed?