Messages in this thread Patch in this message | | | Date | Sun, 26 Feb 2006 22:23:41 +0100 | From | Sam Ravnborg <> | Subject | [PATCH] kbuild: get rid of false positives in section mismatch warnings |
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Following patch committed to my kbuild tree and pushed out. I removes most of the false positives I have seen.
There is still a way to go before we are warning free...
Please note - all the small fixes sent out earlier are not included in my tree. I assume subsystem maintainers ar Andrew will pick them up. But if requested I can drop them in a separate git tree.
Sam
diff-tree 4c8fbca5836aaafd165aa8732d92ab5d4f3a6841 (from cc006288fb538005a14ca4297250abbf0beeb0b9) Author: Sam Ravnborg <sam@mars.ravnborg.org> Date: Sun Feb 26 22:18:11 2006 +0100
kbuild: whitelist false section mismatch warnings In several cases the section mismatch check triggered false warnings. Following patch introduce a whitelist to 'false positives' are not warned of. Two types of patterns are recognised: 1) Typical case when a module parameter is _initdata 2) When a function pointer is assigned to a driver structure In both patterns we rely on the actual name of the variable assigned Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index de0a9ee..663b1ef 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -450,10 +450,93 @@ static char *get_modinfo(void *modinfo, } return NULL; } /** + * Test if string s ends in string sub + * return 0 if match + **/ +static int strrcmp(const char *s, const char *sub) +{ + int slen, sublen; + + if (!s || !sub) + return 1; + + slen = strlen(s); + sublen = strlen(sub); + + if ((slen == 0) || (sublen == 0)) + return 1; + + if (sublen > slen) + return 1; + + return memcmp(s + slen - sublen, sub, sublen); +} + +/** + * Whitelist to allow certain references to pass with no warning. + * Pattern 1: + * If a module parameter is declared __initdata and permissions=0 + * then this is legal despite the warning generated. + * We cannot see value of permissions here, so just ignore + * this pattern. + * The pattern is identified by: + * tosec = .init.data + * fromsec = .data + * atsym =__param* + * + * Pattern 2: + * Many drivers utilise a *_driver container with references to + * add, remove, probe functions etc. + * These functions may often be marked __init and we do not want to + * warn here. + * the pattern is identified by: + * tosec = .init.text | .exit.text + * fromsec = .data + * atsym = *_driver, *_ops, *_probe, *probe_one + **/ +static int secref_whitelist(const char *tosec, const char *fromsec, + const char *atsym) +{ + int f1 = 1, f2 = 1; + const char **s; + const char *pat2sym[] = { + "_driver", + "_ops", + "_probe", + "_probe_one", + NULL + }; + + /* Check for pattern 1 */ + if (strcmp(tosec, ".init.data") != 0) + f1 = 0; + if (strcmp(fromsec, ".data") != 0) + f1 = 0; + if (strncmp(atsym, "__param", strlen("__param")) != 0) + f1 = 0; + + if (f1) + return f1; + + /* Check for pattern 2 */ + if ((strcmp(tosec, ".init.text") != 0) && + (strcmp(tosec, ".exit.text") != 0)) + f2 = 0; + if (strcmp(fromsec, ".data") != 0) + f2 = 0; + + for (s = pat2sym; *s; s++) + if (strrcmp(atsym, *s) == 0) + f1 = 1; + + return f1 && f2; +} + +/** * Find symbol based on relocation record info. * In some cases the symbol supplied is a valid symbol so * return refsym. If st_name != 0 we assume this is a valid symbol. * In other cases the symbol needs to be looked up in the symbol table * based on section and address. @@ -516,10 +599,11 @@ static void find_symbols_between(struct } /** * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. + * Check whitelist before warning - it may be a false positive. **/ static void warn_sec_mismatch(const char *modname, const char *fromsec, struct elf_info *elf, Elf_Sym *sym, Elf_Rela r) { const char *refsymname = ""; @@ -534,10 +618,15 @@ static void warn_sec_mismatch(const char find_symbols_between(elf, r.r_offset, fromsec, &before, &after); refsym = find_elf_symbol(elf, r.r_addend, sym); if (refsym && strlen(elf->strtab + refsym->st_name)) refsymname = elf->strtab + refsym->st_name; + + /* check whitelist - we may ignore it */ + if (before && + secref_whitelist(secname, fromsec, elf->strtab + before->st_name)) + return; if (before && after) { warn("%s - Section mismatch: reference to %s:%s from %s " "between '%s' (at offset 0x%llx) and '%s'\n", modname, secname, refsymname, fromsec, - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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