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[109.81.83.72]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a838396d375sm719241366b.221.2024.08.19.23.24.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Aug 2024 23:24:27 -0700 (PDT) Date: Tue, 20 Aug 2024 08:24:26 +0200 From: Michal Hocko To: Linus Torvalds Cc: Barry Song <21cnbao@gmail.com>, David Hildenbrand , akpm@linux-foundation.org, linux-mm@kvack.org, 42.hyeyoo@gmail.com, cl@linux.com, hailong.liu@oppo.com, hch@infradead.org, iamjoonsoo.kim@lge.com, penberg@kernel.org, rientjes@google.com, roman.gushchin@linux.dev, urezki@gmail.com, v-songbaohua@oppo.com, vbabka@suse.cz, virtualization@lists.linux.dev Subject: Re: [PATCH v3 0/4] mm: clarify nofail memory allocation Message-ID: References: <20240817062449.21164-1-21cnbao@gmail.com> <7050deab-e99c-4c83-b7b9-b5dad42f4e95@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: funpkzt71yjo4tns8y9xsq7sdfa8bkgy X-Rspamd-Queue-Id: 91E5E80011 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1724135069-543240 X-HE-Meta: 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 RgMJ+Lhq zqWXPLPvmsv6pBz5b6kCwjzkRA2G/AH0DwhDCBfF7nhf0g3UgPUYpMeyxFuoyeMMPatNa+k/eBfns+AlSTaXKGeu8NJrOYiS6CGMKYPjt0oZj+nO8p62Cc0IYN/IZoHfRgztQOO0ZzNVrQn0G6EjGfot/2mwDgrih9TaqL2Kis3asiIW4LXLT7I9avFhf91bf1SIath47huS0IJDEYBs2Jmsld1FK+ZB6ex9+4qmIwPWgn8V1swUrIrwxi4rZOBwxJ4tMlMBUYPtO9uVmPsXZwY6s3N332eSJSbXJtZ0jAnveKH4nd2RlNLMMCkXrIiRWAyt7oPgKelKywBgs0NykeODw0iw9OWbO6/eZ0bzvLl/as2UbEn3YQEvouMWa2JRFyist7MobzbIgMZpkUGB7ne87KA== 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 Mon 19-08-24 12:33:17, Linus Torvalds wrote: > On Mon, 19 Aug 2024 at 12:23, Barry Song <21cnbao@gmail.com> wrote: > > > > > > That could be an exploit taking advantage of those improper callers, > > So? > > FIX THE BUGGY CODE. > > Don't make insane and incorrect changes to the MM code and spread > Fear, Uncertainty and Doubt. > > > thus it wouldn’t necessarily result in an immediate oops in callers but > > result in an exploit > > No. Any bug can be an exploit. Don't try to make this something > special by calling it an exploit. > > NULL pointer dereferences are some of the *least* worrisome bugs, > because we don't allow people to mmap the NULL area anyway. > > So just stop spreading FUD. We don't improve the kernel by making > excuses for bugs, we improve it by fixing things. I really do not think that accusing Barry from spreading FUD is fair! I believe there is a good intention behind this initiative and he has used tools that he has available. So rather than throwing FUD arguments I would really like to stick to a technical discussion, please. -- Michal Hocko SUSE Labs