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Arnd Bergmann reported false-positive modpost warnings detected by his randconfig testing of linux-next. Actually, this happens under the combination of CONFIG_MODVERSIONS and CONFIG_TRIM_UNUSED_KSYMS since commit15bfc2348d("modpost: check for static EXPORT_SYMBOL* functions"). For example, arch/arm/config/multi_v7_defconfig + CONFIG_MODVERSIONS + CONFIG_TRIM_UNUSED_KSYMS produces the following false-positives: WARNING: "__lshrdi3" [vmlinux] is a static (unknown) WARNING: "__ashrdi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_lasr" [vmlinux] is a static (unknown) WARNING: "__aeabi_llsr" [vmlinux] is a static (unknown) WARNING: "ftrace_set_clr_event" [vmlinux] is a static (unknown) WARNING: "__muldi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_ulcmp" [vmlinux] is a static (unknown) WARNING: "__ucmpdi2" [vmlinux] is a static (unknown) WARNING: "__aeabi_lmul" [vmlinux] is a static (unknown) WARNING: "__bswapsi2" [vmlinux] is a static (unknown) WARNING: "__bswapdi2" [vmlinux] is a static (unknown) WARNING: "__ashldi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_llsl" [vmlinux] is a static (unknown) The root cause of the problem is not in the modpost, but in the implementation of CONFIG_TRIM_UNUSED_KSYMS. If there is at least one untrimmed symbol in the file, genksyms is invoked to calculate CRC of *all* the exported symbols in that file even if some of them have been trimmed due to no caller existing. As a result, .tmp_*.ver files contain CRC of trimmed symbols, thus unneeded, orphan __crc* symbols are added to objects. It had been harmless until recently. With commit15bfc2348d("modpost: check for static EXPORT_SYMBOL* functions"), it is now harmful because the bogus __crc* symbols make modpost call sym_update_crc() to add the symbols to the hash table, but there is no one that clears the ->is_static member. I gave Fixes to the first commit that uncovered the issue, but the potential problem has long existed since commitf235541699("export.h: allow for per-symbol configurable EXPORT_SYMBOL()"). Fixes:15bfc2348d("modpost: check for static EXPORT_SYMBOL* functions") Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Arnd Bergmann <arnd@arndb.de>
76 lines
2.1 KiB
C
76 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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static struct resword {
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const char *name;
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int token;
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} keywords[] = {
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{ "__GENKSYMS_EXPORT_SYMBOL", EXPORT_SYMBOL_KEYW },
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{ "__asm", ASM_KEYW },
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{ "__asm__", ASM_KEYW },
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{ "__attribute", ATTRIBUTE_KEYW },
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{ "__attribute__", ATTRIBUTE_KEYW },
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{ "__const", CONST_KEYW },
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{ "__const__", CONST_KEYW },
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{ "__extension__", EXTENSION_KEYW },
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{ "__inline", INLINE_KEYW },
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{ "__inline__", INLINE_KEYW },
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{ "__signed", SIGNED_KEYW },
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{ "__signed__", SIGNED_KEYW },
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{ "__typeof", TYPEOF_KEYW },
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{ "__typeof__", TYPEOF_KEYW },
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{ "__volatile", VOLATILE_KEYW },
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{ "__volatile__", VOLATILE_KEYW },
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{ "__builtin_va_list", VA_LIST_KEYW },
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{ "__int128", BUILTIN_INT_KEYW },
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{ "__int128_t", BUILTIN_INT_KEYW },
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{ "__uint128_t", BUILTIN_INT_KEYW },
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// According to rth, c99 defines "_Bool", __restrict", __restrict__", "restrict". KAO
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{ "_Bool", BOOL_KEYW },
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{ "_restrict", RESTRICT_KEYW },
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{ "__restrict__", RESTRICT_KEYW },
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{ "restrict", RESTRICT_KEYW },
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{ "asm", ASM_KEYW },
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// attribute commented out in modutils 2.4.2. People are using 'attribute' as a
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// field name which breaks the genksyms parser. It is not a gcc keyword anyway.
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// KAO. },
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// { "attribute", ATTRIBUTE_KEYW },
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{ "auto", AUTO_KEYW },
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{ "char", CHAR_KEYW },
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{ "const", CONST_KEYW },
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{ "double", DOUBLE_KEYW },
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{ "enum", ENUM_KEYW },
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{ "extern", EXTERN_KEYW },
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{ "float", FLOAT_KEYW },
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{ "inline", INLINE_KEYW },
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{ "int", INT_KEYW },
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{ "long", LONG_KEYW },
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{ "register", REGISTER_KEYW },
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{ "short", SHORT_KEYW },
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{ "signed", SIGNED_KEYW },
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{ "static", STATIC_KEYW },
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{ "struct", STRUCT_KEYW },
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{ "typedef", TYPEDEF_KEYW },
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{ "typeof", TYPEOF_KEYW },
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{ "union", UNION_KEYW },
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{ "unsigned", UNSIGNED_KEYW },
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{ "void", VOID_KEYW },
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{ "volatile", VOLATILE_KEYW },
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};
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#define NR_KEYWORDS (sizeof(keywords)/sizeof(struct resword))
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static int is_reserved_word(register const char *str, register unsigned int len)
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{
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int i;
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for (i = 0; i < NR_KEYWORDS; i++) {
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struct resword *r = keywords + i;
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int l = strlen(r->name);
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if (len == l && !memcmp(str, r->name, len))
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return r->token;
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}
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return -1;
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}
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