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b=wQDHiOzwdGwAAGbXNtUr11IgHGTLML+ZTgybkSYzTVxKRs3vq9IMLbEGrSvxeJ/ljC+BuP Us+utJ17UGPll7CQ== Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: Re: [RFC PATCH bpf-next v3 1/2] ftrace: deprecate disabling via ftrace_enabled sysctl From: Miroslav Benes To: Andrey Grodzovsky Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, live-patching@vger.kernel.org, rostedt@goodmis.org, mbenes@suse.cz, jolsa@kernel.org, mhiramat@kernel.org, jpoimboe@kernel.org, joe.lawrence@redhat.com, mark.rutland@arm.com, corbet@lwn.net, stable@vger.kernel.org, linux-open-source@crowdstrike.com In-Reply-To: <20260806153000.4184871-2-andrey.grodzovsky@crowdstrike.com> References: <20260806153000.4184871-1-andrey.grodzovsky@crowdstrike.com> <20260806153000.4184871-2-andrey.grodzovsky@crowdstrike.com> Date: Mon, 24 Aug 2026 14:30:06 +0200 Message-Id: <178757460647.29054.9328797950595292140.b4-review@b4> X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; 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MID_RHS_NOT_FQDN(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RCPT_COUNT_TWELVE(0.00)[14]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DIRECT_TO_MX(0.00)[b4 0.17-dev]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[crowdstrike.com:email,suse.cz:email,suse.cz:dkim]; DNSWL_BLOCKED(0.00)[2a07:de40:b2bf:1b::12ef:from]; RCVD_COUNT_ZERO(0.00)[0]; FROM_EQ_ENVFROM(0.00)[]; DKIM_TRACE(0.00)[suse.cz:+] X-Spam-Score: 17.40 X-Spam-Level: ***************** X-Spamd-Bar: +++++++++++++++++ X-Rspamd-Queue-Id: 77B1D1F456 X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Flag: YES X-Rspamd-Action: add header X-Spam: Yes On Thu, 06 Aug 2026 11:29:59 -0400, Andrey Grodzovsky wrote: > Writing 0 to kernel.ftrace_enabled has not reliably disabled ftrace > for years (FTRACE_OPS_FL_PERMANENT users already block it, and more > callers rely on ftrace always being on). Refuse the write instead of > leaving it in an inconsistent "disables some, not all" state: return > -EOPNOTSUPP and log a message. Reads and enabling (writing 1) are > unaffected. > > [...] Reviewed-by: Miroslav Benes -- Miroslav