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Mon, 9 Feb 2026 13:41:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770644516; bh=Ew7kN46rhGDM4dEiPsUsVqK/GgQOgN3YtDNu7vHLVtw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=QbS3j8toBchCyyOG4nENlUg2D4KmlTtxqT2G/uTWdMpPr6141acVfjkqkreoHBAFz tZ3XpuiHA46IJzEPNsxDfIELspw/dngnfh3WvCNPL9OBeXIhPUEL68qFNJeMxO2RE2 nGY9lRw5pGAIdBHtfvAJATm0kYt93zY9vveYVKJed6Yh7MgjtCuPswtdzNPnPU3soi yDWTIW5YEeFR2X/k5UGoyRCsgWfhMErov5XltYJmXTXD4gzzheqW1w8tXuDlCJX94e le+kDh3zM8NsqQXfHdWTOlTfufJQfcU5wJVwFywPVnAyj3x1OJ7Jdf3h/nABIqdtL3 qi20Z4MC/uYPg== Message-ID: <5cfae419-427a-471b-8bbe-645f56442e2c@kernel.org> Date: Mon, 9 Feb 2026 14:41:51 +0100 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] powerpc/text-patching: Fix possible stringop-overread compilation error To: Xie Yuanbin , andriy.shevchenko@intel.com, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, kees@kernel.org, andy@kernel.org Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, lilinjie8@huawei.com, liaohua4@huawei.com References: <20260209132510.84205-1-xieyuanbin1@huawei.com> Content-Language: fr-FR From: "Christophe Leroy (CS GROUP)" In-Reply-To: <20260209132510.84205-1-xieyuanbin1@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 09/02/2026 à 14:25, Xie Yuanbin a écrit : > On Fri, 6 Feb 2026 20:53:55 +0100, Christophe Leroy (CS GROUP) wrote: >> Le 06/02/2026 à 19:26, Kees Cook a écrit : >>> >>> Isn't it possible to do this and not need __compiletime_strlen at all? >>> >>> n_len = strnlen(name, min(__member_size(name), KSYM_NAME_LEN)); >> >> ppc_kallsyms_lookup_name() only has two callers and they call it with a >> built-in string. I think we can do something a lot simpler, something >> like (untested): >> >> static inline unsigned long __ppc_kallsyms_lookup_name(const char *name) >> { >> unsigned long addr = kallsyms_lookup_name(name); >> >> if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr) >> addr = ppc_function_entry((void *)addr); >> >> return addr; >> } >> >> #ifdef CONFIG_PPC64_ELF_ABI_V1 >> #define ppc_kallsyms_lookup_name(x) __ppc_kallsyms_lookup_name("." ## x); >> #else >> #define ppc_kallsyms_lookup_name(x) __ppc_kallsyms_lookup_name(x) >> #endif >> >> Christophe > > When CONFIG_PPC64_ELF_ABI_V1=y, it seems that the try of lookupinp > the original non-dot symbol is missing. > > What about this (Only the compilation test is performed): > ```c > static inline unsigned long __ppc_kallsyms_lookup_name(const char *name) > { > unsigned long addr = kallsyms_lookup_name(name); > > if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr) > addr = ppc_function_entry((void *)addr); > > return addr; > } > > #define ppc_kallsyms_lookup_name(x) ({ \ > unsigned long addr = 0; \ > if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1)) \ > addr = __ppc_kallsyms_lookup_name("." x); \ > if (!addr) \ > addr = __ppc_kallsyms_lookup_name(x); \ > addr; \ > }) > ``` Good point. To avoid duplicating the string I'd suggest: static inline unsigned long __ppc_kallsyms_lookup_name(const char *name) { unsigned long addr = kallsyms_lookup_name(name); if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) && !addr) addr = kallsyms_lookup_name(name + 1); if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr) addr = ppc_function_entry((void *)addr); return addr; } #ifdef CONFIG_PPC64_ELF_ABI_V1 #define ppc_kallsyms_lookup_name(x) __ppc_kallsyms_lookup_name("." x); #else #define ppc_kallsyms_lookup_name(x) __ppc_kallsyms_lookup_name(x) #endif