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a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1775728055; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VPTesRUCHX4NMM4UTkklTPtjujPQJY3bhq7UEGu0/No=; b=qGty1Csu8CtH/HBvYVSB97KLSh/Zf0h3sHXB5bRtlel2pwq2y66LizfV3IbLtU6K8q8KpJ jg+6cBfC6Fvc2kckjCR9176mdUNldLHs/b/9PBLT3mhAw8Dhyg63YOgImmJQPjsMPt1a02 e5QpJ6E0AV5XHovqDiSXK0/da9Q34Jw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1775728055; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VPTesRUCHX4NMM4UTkklTPtjujPQJY3bhq7UEGu0/No=; b=V4IyF8XkQQ52NdkV3fldKsNVjybo5j4XrfelDSTlXIuXPGU+3a/5TamSYcCWtjXXVUUgjl +ZBd7TbKTqlBfXDw== Date: Thu, 9 Apr 2026 11:47:35 +0200 (CEST) From: Miroslav Benes To: Yafang Shao cc: jpoimboe@kernel.org, jikos@kernel.org, pmladek@suse.com, joe.lawrence@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, kpsingh@kernel.org, mattbobrowski@google.com, song@kernel.org, jolsa@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, memxor@gmail.com, yonghong.song@linux.dev, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [RFC PATCH 2/4] trace: Allow kprobes to override livepatched functions In-Reply-To: <20260402092607.96430-3-laoar.shao@gmail.com> Message-ID: References: <20260402092607.96430-1-laoar.shao@gmail.com> <20260402092607.96430-3-laoar.shao@gmail.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) 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=US-ASCII X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCVD_COUNT_ZERO(0.00)[0]; TAGGED_RCPT(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; FUZZY_RATELIMITED(0.00)[rspamd.com]; FREEMAIL_TO(0.00)[gmail.com]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RCPT_COUNT_TWELVE(0.00)[23]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[kernel.org,suse.com,redhat.com,goodmis.org,efficios.com,google.com,iogearbox.net,linux.dev,gmail.com,vger.kernel.org]; MID_RHS_MATCH_FROMTLD(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_SOME(0.00)[] X-Spam-Flag: NO X-Spam-Score: -2.80 X-Spam-Level: Hi, On Thu, 2 Apr 2026, Yafang Shao wrote: > Introduce the ability for kprobes to override the return values of > functions that have been livepatched. This functionality is guarded by the > CONFIG_KPROBE_OVERRIDE_KLP_FUNC configuration option. this is imprecise if I read the code correctly. You want to override live patch functions, not the original ones which are live patched. I also think that if nothing else, it needs to be more specific then just checking mod->klp. It should check if a function itself in klp module is overridable to keep it as limited as possible. Even with that, the concerns expressed by the others still apply. --- Miroslav