{"id":2233271,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2233271/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260506021143.13797-1-xieyuanbin1@huawei.com/","project":{"id":2,"url":"http://patchwork.ozlabs.org/api/1.1/projects/2/?format=json","name":"Linux PPC development","link_name":"linuxppc-dev","list_id":"linuxppc-dev.lists.ozlabs.org","list_email":"linuxppc-dev@lists.ozlabs.org","web_url":"https://github.com/linuxppc/wiki/wiki","scm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git","webscm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/"},"msgid":"<20260506021143.13797-1-xieyuanbin1@huawei.com>","date":"2026-05-06T02:11:43","name":"[V2] powerpc/text-patching: simplify the implementation of ppc_kallsyms_lookup_name()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"d4c92f77adeb129a6ba8e45e50eae7ae6bbc0a5b","submitter":{"id":92591,"url":"http://patchwork.ozlabs.org/api/1.1/people/92591/?format=json","name":"Xie Yuanbin","email":"xieyuanbin1@huawei.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260506021143.13797-1-xieyuanbin1@huawei.com/mbox/","series":[{"id":502916,"url":"http://patchwork.ozlabs.org/api/1.1/series/502916/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=502916","date":"2026-05-06T02:11:43","name":"[V2] powerpc/text-patching: simplify the implementation of ppc_kallsyms_lookup_name()","version":2,"mbox":"http://patchwork.ozlabs.org/series/502916/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2233271/comments/","check":"success","checks":"http://patchwork.ozlabs.org/api/patches/2233271/checks/","tags":{},"headers":{"Return-Path":"\n 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q=dns/txt;\n\th=From;\n\tbh=HMqHW+wl1jJEGGmKKzAemuQMuR+F3aEoMElUydaAiH0=;\n\tb=yNTbuRmolm/SEoq+MkaSp/cYhtRgK4nsCKZwtO3fqA6+9ZhleNRt68Jnv2/RrJISaYn6gSd+u\n\taCx6xYY7OF2l0Uw8iMfP40fycKvDbh7HTo3w3AmhHFNraYyNk8UjMKjfYVfDjZn7E4qgOx7xeYc\n\tcbrTTJrKbUV2daiXo8CM/wE=","v=1; a=rsa-sha256; d=huawei.com; s=dkim;\n\tc=relaxed/relaxed; q=dns/txt;\n\th=From;\n\tbh=HMqHW+wl1jJEGGmKKzAemuQMuR+F3aEoMElUydaAiH0=;\n\tb=yNTbuRmolm/SEoq+MkaSp/cYhtRgK4nsCKZwtO3fqA6+9ZhleNRt68Jnv2/RrJISaYn6gSd+u\n\taCx6xYY7OF2l0Uw8iMfP40fycKvDbh7HTo3w3AmhHFNraYyNk8UjMKjfYVfDjZn7E4qgOx7xeYc\n\tcbrTTJrKbUV2daiXo8CM/wE="],"From":"Xie Yuanbin ","To":", , ,\n\t, , ","CC":", ,\n\t, , ","Subject":"[PATCH V2] powerpc/text-patching: simplify the implementation of\n ppc_kallsyms_lookup_name()","Date":"Wed, 6 May 2026 10:11:43 +0800","Message-ID":"<20260506021143.13797-1-xieyuanbin1@huawei.com>","X-Mailer":"git-send-email 2.53.0","X-Mailing-List":"linuxppc-dev@lists.ozlabs.org","List-Id":"","List-Help":"","List-Owner":"","List-Post":"","List-Archive":",\n ","List-Subscribe":",\n ,\n ","List-Unsubscribe":"","Precedence":"list","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Content-Type":"text/plain","X-Originating-IP":"[10.67.109.17]","X-ClientProxiedBy":"kwepems500001.china.huawei.com (7.221.188.70) To\n kwepemj100009.china.huawei.com (7.202.194.3)","X-Spam-Status":"No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID,\n\tDKIM_VALID_AU,DKIM_VALID_EF,HK_RANDOM_ENVFROM,HK_RANDOM_FROM,\n\tRCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS autolearn=disabled\n\tversion=4.0.1 OzLabs 8","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org"},"content":"ppc_kallsyms_lookup_name() is called only twice in the kernel code, and\nthe parameters are all constant strings. strnlen(name, KSYM_NAME_LEN) is\ncalled inside ppc_kallsyms_lookup_name(), when the compiler detects that\nKSYM_NAME_LEN is larger then the constant strings,\nthe following error will be triggered:\n```log\n CC arch/powerpc/kernel/optprobes.o\nIn file included from ./arch/powerpc/include/asm/kprobes.h:24,\n from ./include/linux/kprobes.h:31,\n from arch/powerpc/kernel/optprobes.c:8:\nIn function 'ppc_kallsyms_lookup_name',\n inlined from 'arch_prepare_optimized_kprobe' at arch/powerpc/kernel/optprobes.c:209:21:\n./arch/powerpc/include/asm/text-patching.h:232:13: error: 'strnlen' specified bound 512 exceeds source size 19 [-Werror=stringop-overread]\n 232 | if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)\n | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~\nIn function 'ppc_kallsyms_lookup_name',\n inlined from 'arch_prepare_optimized_kprobe' at arch/powerpc/kernel/optprobes.c:210:22:\n./arch/powerpc/include/asm/text-patching.h:232:13: error: 'strnlen' specified bound 512 exceeds source size 13 [-Werror=stringop-overread]\n 232 | if (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)\n | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~\ncc1: all warnings being treated as errors\n```\n\nThe error can be reproduced in the following ways:\nUse lastest linux-next source, change ppc_kallsyms_lookup_name() to\n__always_inline, use default ppc64_defconfig, set CONFIG_EXPERT=y,\nCONFIG_PPC64_BIG_ENDIAN_ELF_ABI_V2=n, CONFIG_CC_OPTIMIZE_FOR_SIZE=y,\nand use gcc-14 or a later version for compilation.\n\nSince ppc_kallsyms_lookup_name() is called only twice in the kernel,\nand the parameters are all constant strins, simplify the implementation\nof ppc_kallsyms_lookup_name() and avoid calling strnlen().\n\nCc: Andy Shevchenko \nCc: Kees Cook \nSuggested-by: Christophe Leroy (CS GROUP) \nSigned-off-by: Xie Yuanbin \n---\nv1->v2: https://lore.kernel.org/20260205100517.292858-2-xieyuanbin1@huawei.com\n - Not use strlen()\n\n arch/powerpc/include/asm/text-patching.h | 50 ++++++++----------------\n 1 file changed, 17 insertions(+), 33 deletions(-)","diff":"diff --git a/arch/powerpc/include/asm/text-patching.h b/arch/powerpc/include/asm/text-patching.h\nindex e7f14720f630..2d3f698cb4f1 100644\n--- a/arch/powerpc/include/asm/text-patching.h\n+++ b/arch/powerpc/include/asm/text-patching.h\n@@ -221,39 +221,23 @@ static inline unsigned long ppc_global_function_entry(void *func)\n * - For ABIv1, we lookup the dot variant.\n * - For ABIv2, we return the local entry point.\n */\n-static inline unsigned long ppc_kallsyms_lookup_name(const char *name)\n-{\n-\tunsigned long addr;\n-#ifdef CONFIG_PPC64_ELF_ABI_V1\n-\t/* check for dot variant */\n-\tchar dot_name[1 + KSYM_NAME_LEN];\n-\tbool dot_appended = false;\n-\n-\tif (strnlen(name, KSYM_NAME_LEN) >= KSYM_NAME_LEN)\n-\t\treturn 0;\n-\n-\tif (name[0] != '.') {\n-\t\tdot_name[0] = '.';\n-\t\tdot_name[1] = '\\0';\n-\t\tstrlcat(dot_name, name, sizeof(dot_name));\n-\t\tdot_appended = true;\n-\t} else {\n-\t\tdot_name[0] = '\\0';\n-\t\tstrlcat(dot_name, name, sizeof(dot_name));\n-\t}\n-\taddr = kallsyms_lookup_name(dot_name);\n-\tif (!addr && dot_appended)\n-\t\t/* Let's try the original non-dot symbol lookup\t*/\n-\t\taddr = kallsyms_lookup_name(name);\n-#elif defined(CONFIG_PPC64_ELF_ABI_V2)\n-\taddr = kallsyms_lookup_name(name);\n-\tif (addr)\n-\t\taddr = ppc_function_entry((void *)addr);\n-#else\n-\taddr = kallsyms_lookup_name(name);\n-#endif\n-\treturn addr;\n-}\n+static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)\n+{\n+\tunsigned long addr = kallsyms_lookup_name(name);\n+\n+\tif (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) && !addr)\n+\t\taddr = kallsyms_lookup_name(name + 1);\n+\tif (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)\n+\t\taddr = ppc_function_entry((void *)addr);\n+\n+\treturn addr;\n+}\n+\n+#ifdef CONFIG_PPC64_ELF_ABI_V1\n+#define ppc_kallsyms_lookup_name(x)\t__ppc_kallsyms_lookup_name(\".\" x)\n+#else\n+#define ppc_kallsyms_lookup_name(x)\t__ppc_kallsyms_lookup_name(x)\n+#endif\n \n /*\n * Some instruction encodings commonly used in dynamic ftracing\n","prefixes":["V2"]}