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Tue, 20 Aug 2024 13:30:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id DG5eHWCaxGbpDwAAD6G6ig (envelope-from ); Tue, 20 Aug 2024 13:30:08 +0000 Date: Tue, 20 Aug 2024 15:29:08 +0200 From: Cyril Hrubis To: Miao Wang Cc: Greg Kroah-Hartman , Xi Ruoyao , Huacai Chen , loongarch@lists.linux.dev, Sasha Levin , stable@vger.kernel.org, WANG Xuerui , linux-api@vger.kernel.org Subject: Re: It is correct to introduce new sys calls to stable versions? Message-ID: References: Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Level: X-Spamd-Result: default: False [-3.27 / 50.00]; BAYES_HAM(-3.00)[99.99%]; SUBJECT_ENDS_QUESTION(1.00)[]; NEURAL_HAM_LONG(-1.00)[-0.998]; NEURAL_HAM_SHORT(-0.18)[-0.880]; MIME_GOOD(-0.10)[text/plain]; FREEMAIL_TO(0.00)[gmail.com]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; MISSING_XM_UA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCPT_COUNT_SEVEN(0.00)[9]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_BLOCKED(0.00)[rspamd.com]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:email,yuki.lan:mid,imap1.dmz-prg2.suse.org:helo] X-Spam-Score: -3.27 X-Spam-Flag: NO Hi! > I wonder if it is correct to add new syscalls, which actually changes > the kernel features, in stable releases, as it might confuse downstream > developers because they may assume the existence of a certain feature > after a certain version. Just a side note, one thing I've learned by maintaining the Linux Test Project is that the kernel version is a lie. You should not use the kernel version for anything, never. All distributions rutinely backport various new functionalities to older kernels and only reliable way how to make sure something is implemented is to call the syscall and check the return value. That being said I have no idea what rules apply to stable trees. -- Cyril Hrubis chrubis@suse.cz