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dkim=pass header.d=soleen.com header.s=google header.b=JPDXpPqv; dmarc=none; spf=pass (imf07.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.208.54 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com X-Stat-Signature: wzqzzp5pn8fisnw1iqhc8neoqhd8y3df X-Rspam-User: X-HE-Tag: 1662928991-867874 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: On Sun, Sep 11, 2022 at 12:08 PM Matthew Wilcox wrote: > > On Sun, Sep 11, 2022 at 09:59:22AM +0000, Pasha Tatashin wrote: > > Currently, page_table_check when detects errors panics kernel. Instead, > > print a warning, and panic only when specifically requested via kernel > > parameter: > > > > page_table_check=panic > > Why are the page table checks so special that they deserve their own > command line parameter? Why shouldn't this be controlled by the usual > panic_on_warn option? page_table_check can be used as a security feature preventing false page sharing between address spaces. For example, at Google we want it to keep enabled on production systems, yet we do not want to enable panic_on_warn as it would cause panics for many other reasons which are security unrelated. Pasha