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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-39eae979637sm15148655f8f.53.2025.04.15.10.39.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Apr 2025 10:39:41 -0700 (PDT) Date: Tue, 15 Apr 2025 18:39:34 +0100 From: David Laight To: Steven Rostedt Cc: Peter Zijlstra , Arnd Bergmann , Josh Poimboeuf , Arnd Bergmann , Masahiro Yamada , Rae Moar , Shuah Khan , Sergio =?UTF-8?B?R29uesOhbGV6?= Collado , David Gow , Nathan Chancellor , Nicolas Schier , Mostafa Saleh , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] scripts/mksysmap: skip objtool __pfx_ symbols Message-ID: <20250415183934.46f4ed6f@pumpkin> In-Reply-To: <20250412102218.560196c0@batman.local.home> References: <20250328112156.2614513-1-arnd@kernel.org> <20250411065054.GM9833@noisy.programming.kicks-ass.net> <0073e739-e3aa-4743-ad2d-29d7c969f454@app.fastmail.com> <20250411105849.GA5600@noisy.programming.kicks-ass.net> <20250412102218.560196c0@batman.local.home> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 12 Apr 2025 10:22:18 -0400 Steven Rostedt wrote: ... > I just hit this on my allyesconfig build: > > NM .tmp_vmlinux1.syms > KSYMS .tmp_vmlinux1.kallsyms.S > Symbol __cfi_snnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nnng1h2i3j4k5l6m7ng1h2i3j4k5l6m7nng1h2i3j4k5l6m7ng1h2i3j4k5l6m7n too long for kallsyms (517 >= 512). > Please increase KSYM_NAME_LEN both in kernel and kallsyms.c ... > > I grepped for that symbol and it lives in: lib/tests/longest_symbol_kunit.o Looks like it is carefully counted to be 511 characters. And then the compiler adds __cfi_ making 517. I guess the test could be changed? Is it possible to remove the __cfi_ symbols (to save kernel memory) and then use a single bit to indicate that the previous few bytes (the same number for all such symbols) belong to the following symbol? Then stack backtraces would say "foo-n" instead "__cfi_foo+n". David