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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com Content-Type: text/plain; charset="UTF-8" X-Spamd-Result: default: False [3.60 / 9.00]; IRL_BL_25(2.00)[52.25.139.140:received]; SUSPICIOUS_RECIPS(1.50)[]; RCVD_NO_TLS_LAST(0.10)[]; MIME_GOOD(-0.10)[text/plain]; BAD_REP_POLICIES(0.10)[]; BAYES_HAM(-0.00)[18.64%]; R_SPF_ALLOW(0.00)[+a:sin.source.kernel.org]; RCPT_COUNT_TWELVE(0.00)[39]; DMARC_POLICY_ALLOW(0.00)[kernel.org,none]; R_DKIM_ALLOW(0.00)[kernel.org:s=k20201202]; MIME_TRACE(0.00)[0:+]; FROM_EQ_ENVFROM(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; DKIM_TRACE(0.00)[kernel.org:+]; RCVD_COUNT_THREE(0.00)[4]; TAGGED_RCPT(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[linux-mm@kvack.org]; FROM_HAS_DN(0.00)[]; ARC_SIGNED(0.00)[hostedemail.com:s=arc-20220608:i=1]; RCVD_VIA_SMTP_AUTH(0.00)[] X-Rspamd-Queue-Id: F39C0140002 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: aochkh1fsyh35szxgthmxi33dp9ktbrf X-HE-Tag: 1670107816-24351 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 Fri, Dec 2, 2022 at 4:44 PM Rick Edgecombe wrote: > > So since 32 bit is not easy to support, and there are likely not many > users. More cleanly don't support 32 bit signals in a 64 bit address > space by not allowing 32 bit ABI signal handlers when shadow stack is > enabled. Do this by clearing any 32 bit ABI signal handlers when shadow > stack is enabled, and disallow any further 32 bit ABI signal handlers. > Also, return an error code for the clone operations when in a 32 bit > syscall. > This seems unfortunate. The result will be a highly incomprehensible crash. Maybe instead deny enabling shadow stack in the first place? Or at least pr_warn_once if anything gets flushed.