From 4a4962263f07d14660849ec134ee42b63e95ea9a Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 6 Jul 2009 14:50:42 +0100 Subject: module: reduce symbol table for loaded modules (v2) Discard all symbols not interesting for kallsyms use: absolute, section, and in the common case (!KALLSYMS_ALL) data ones. Signed-off-by: Jan Beulich Signed-off-by: Rusty Russell --- kernel/module.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 87 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index e6bc4b2..97f4d5e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1862,13 +1862,68 @@ static char elf_type(const Elf_Sym *sym, return '?'; } +static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs, + unsigned int shnum) +{ + const Elf_Shdr *sec; + + if (src->st_shndx == SHN_UNDEF + || src->st_shndx >= shnum + || !src->st_name) + return false; + + sec = sechdrs + src->st_shndx; + if (!(sec->sh_flags & SHF_ALLOC) +#ifndef CONFIG_KALLSYMS_ALL + || !(sec->sh_flags & SHF_EXECINSTR) +#endif + || (sec->sh_entsize & INIT_OFFSET_MASK)) + return false; + + return true; +} + +static unsigned long layout_symtab(struct module *mod, + Elf_Shdr *sechdrs, + unsigned int symindex, + const Elf_Ehdr *hdr, + const char *secstrings) +{ + unsigned long symoffs; + Elf_Shdr *symsect = sechdrs + symindex; + const Elf_Sym *src; + unsigned int i, nsrc, ndst; + + /* Put symbol section at end of init part of module. */ + symsect->sh_flags |= SHF_ALLOC; + symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect, + symindex) | INIT_OFFSET_MASK; + DEBUGP("\t%s\n", secstrings + symsect->sh_name); + + src = (void *)hdr + symsect->sh_offset; + nsrc = symsect->sh_size / sizeof(*src); + for (ndst = i = 1; i < nsrc; ++i, ++src) + if (is_core_symbol(src, sechdrs, hdr->e_shnum)) + ++ndst; + + /* Append room for core symbols at end of core part. */ + symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1); + mod->core_size = symoffs + ndst * sizeof(Elf_Sym); + + return symoffs; +} + static void add_kallsyms(struct module *mod, Elf_Shdr *sechdrs, + unsigned int shnum, unsigned int symindex, unsigned int strindex, + unsigned long symoffs, const char *secstrings) { - unsigned int i; + unsigned int i, ndst; + const Elf_Sym *src; + Elf_Sym *dst; mod->symtab = (void *)sechdrs[symindex].sh_addr; mod->num_symtab = sechdrs[symindex].sh_size / sizeof(Elf_Sym); @@ -1878,12 +1933,32 @@ static void add_kallsyms(struct module *mod, for (i = 0; i < mod->num_symtab; i++) mod->symtab[i].st_info = elf_type(&mod->symtab[i], sechdrs, secstrings, mod); + + mod->core_symtab = dst = mod->module_core + symoffs; + src = mod->symtab; + *dst = *src; + for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) { + if (!is_core_symbol(src, sechdrs, shnum)) + continue; + dst[ndst] = *src; + ++ndst; + } + mod->core_num_syms = ndst; } #else +static inline unsigned long layout_symtab(struct module *mod, + Elf_Shdr *sechdrs, + unsigned int symindex, + const Elf_Hdr *hdr, + const char *secstrings) +{ +} static inline void add_kallsyms(struct module *mod, Elf_Shdr *sechdrs, + unsigned int shnum, unsigned int symindex, unsigned int strindex, + unsigned long symoffs, const char *secstrings) { } @@ -1959,6 +2034,9 @@ static noinline struct module *load_module(void __user *umod, struct module *mod; long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ +#ifdef CONFIG_KALLSYMS + unsigned long symoffs; +#endif mm_segment_t old_fs; DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n", @@ -2041,8 +2119,7 @@ static noinline struct module *load_module(void __user *umod, sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC; #ifdef CONFIG_KALLSYMS - /* Keep symbol and string tables for decoding later. */ - sechdrs[symindex].sh_flags |= SHF_ALLOC; + /* Keep string table for decoding later. */ sechdrs[strindex].sh_flags |= SHF_ALLOC; #endif @@ -2109,6 +2186,7 @@ static noinline struct module *load_module(void __user *umod, this is done generically; there doesn't appear to be any special cases for the architectures. */ layout_sections(mod, hdr, sechdrs, secstrings); + symoffs = layout_symtab(mod, sechdrs, symindex, hdr, secstrings); /* Do the allocs. */ ptr = module_alloc_update_bounds(mod->core_size); @@ -2313,7 +2391,8 @@ static noinline struct module *load_module(void __user *umod, percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr, sechdrs[pcpuindex].sh_size); - add_kallsyms(mod, sechdrs, symindex, strindex, secstrings); + add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex, + symoffs, secstrings); if (!mod->taints) { struct _ddebug *debug; @@ -2491,6 +2570,10 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, /* Drop initial reference. */ module_put(mod); trim_init_extable(mod); +#ifdef CONFIG_KALLSYMS + mod->num_symtab = mod->core_num_syms; + mod->symtab = mod->core_symtab; +#endif module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; -- cgit v1.1 From 554bdfe5acf3715e87c8d5e25a4f9a896ac9f014 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 6 Jul 2009 14:51:44 +0100 Subject: module: reduce string table for loaded modules (v2) Also remove all parts of the string table (referenced by the symbol table) that are not needed for kallsyms use (i.e. which were only referenced by symbols discarded by the previous patch, or not referenced at all for whatever reason). Signed-off-by: Jan Beulich Signed-off-by: Rusty Russell --- kernel/module.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 56 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 97f4d5e..39827c3 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1886,12 +1886,17 @@ static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs, static unsigned long layout_symtab(struct module *mod, Elf_Shdr *sechdrs, unsigned int symindex, + unsigned int strindex, const Elf_Ehdr *hdr, - const char *secstrings) + const char *secstrings, + unsigned long *pstroffs, + unsigned long *strmap) { unsigned long symoffs; Elf_Shdr *symsect = sechdrs + symindex; + Elf_Shdr *strsect = sechdrs + strindex; const Elf_Sym *src; + const char *strtab; unsigned int i, nsrc, ndst; /* Put symbol section at end of init part of module. */ @@ -1902,14 +1907,31 @@ static unsigned long layout_symtab(struct module *mod, src = (void *)hdr + symsect->sh_offset; nsrc = symsect->sh_size / sizeof(*src); + strtab = (void *)hdr + strsect->sh_offset; for (ndst = i = 1; i < nsrc; ++i, ++src) - if (is_core_symbol(src, sechdrs, hdr->e_shnum)) + if (is_core_symbol(src, sechdrs, hdr->e_shnum)) { + unsigned int j = src->st_name; + + while(!__test_and_set_bit(j, strmap) && strtab[j]) + ++j; ++ndst; + } /* Append room for core symbols at end of core part. */ symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1); mod->core_size = symoffs + ndst * sizeof(Elf_Sym); + /* Put string table section at end of init part of module. */ + strsect->sh_flags |= SHF_ALLOC; + strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect, + strindex) | INIT_OFFSET_MASK; + DEBUGP("\t%s\n", secstrings + strsect->sh_name); + + /* Append room for core symbols' strings at end of core part. */ + *pstroffs = mod->core_size; + __set_bit(0, strmap); + mod->core_size += bitmap_weight(strmap, strsect->sh_size); + return symoffs; } @@ -1919,11 +1941,14 @@ static void add_kallsyms(struct module *mod, unsigned int symindex, unsigned int strindex, unsigned long symoffs, - const char *secstrings) + unsigned long stroffs, + const char *secstrings, + unsigned long *strmap) { unsigned int i, ndst; const Elf_Sym *src; Elf_Sym *dst; + char *s; mod->symtab = (void *)sechdrs[symindex].sh_addr; mod->num_symtab = sechdrs[symindex].sh_size / sizeof(Elf_Sym); @@ -1941,16 +1966,25 @@ static void add_kallsyms(struct module *mod, if (!is_core_symbol(src, sechdrs, shnum)) continue; dst[ndst] = *src; + dst[ndst].st_name = bitmap_weight(strmap, dst[ndst].st_name); ++ndst; } mod->core_num_syms = ndst; + + mod->core_strtab = s = mod->module_core + stroffs; + for (*s = 0, i = 1; i < sechdrs[strindex].sh_size; ++i) + if (test_bit(i, strmap)) + *++s = mod->strtab[i]; } #else static inline unsigned long layout_symtab(struct module *mod, Elf_Shdr *sechdrs, unsigned int symindex, + unsigned int strindex, const Elf_Hdr *hdr, - const char *secstrings) + const char *secstrings, + unsigned long *pstroffs, + unsigned long *strmap) { } static inline void add_kallsyms(struct module *mod, @@ -1959,7 +1993,9 @@ static inline void add_kallsyms(struct module *mod, unsigned int symindex, unsigned int strindex, unsigned long symoffs, - const char *secstrings) + unsigned long stroffs, + const char *secstrings, + const unsigned long *strmap) { } #endif /* CONFIG_KALLSYMS */ @@ -2035,7 +2071,7 @@ static noinline struct module *load_module(void __user *umod, long err = 0; void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ #ifdef CONFIG_KALLSYMS - unsigned long symoffs; + unsigned long symoffs, stroffs, *strmap; #endif mm_segment_t old_fs; @@ -2118,10 +2154,6 @@ static noinline struct module *load_module(void __user *umod, /* Don't keep modinfo and version sections. */ sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC; -#ifdef CONFIG_KALLSYMS - /* Keep string table for decoding later. */ - sechdrs[strindex].sh_flags |= SHF_ALLOC; -#endif /* Check module struct version now, before we try to use module. */ if (!check_modstruct_version(sechdrs, versindex, mod)) { @@ -2157,6 +2189,13 @@ static noinline struct module *load_module(void __user *umod, goto free_hdr; } + strmap = kzalloc(BITS_TO_LONGS(sechdrs[strindex].sh_size) + * sizeof(long), GFP_KERNEL); + if (!strmap) { + err = -ENOMEM; + goto free_mod; + } + if (find_module(mod->name)) { err = -EEXIST; goto free_mod; @@ -2186,7 +2225,8 @@ static noinline struct module *load_module(void __user *umod, this is done generically; there doesn't appear to be any special cases for the architectures. */ layout_sections(mod, hdr, sechdrs, secstrings); - symoffs = layout_symtab(mod, sechdrs, symindex, hdr, secstrings); + symoffs = layout_symtab(mod, sechdrs, symindex, strindex, hdr, + secstrings, &stroffs, strmap); /* Do the allocs. */ ptr = module_alloc_update_bounds(mod->core_size); @@ -2392,7 +2432,9 @@ static noinline struct module *load_module(void __user *umod, sechdrs[pcpuindex].sh_size); add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex, - symoffs, secstrings); + symoffs, stroffs, secstrings, strmap); + kfree(strmap); + strmap = NULL; if (!mod->taints) { struct _ddebug *debug; @@ -2481,6 +2523,7 @@ static noinline struct module *load_module(void __user *umod, percpu_modfree(percpu); free_mod: kfree(args); + kfree(strmap); free_hdr: vfree(hdr); return ERR_PTR(err); @@ -2573,6 +2616,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, #ifdef CONFIG_KALLSYMS mod->num_symtab = mod->core_num_syms; mod->symtab = mod->core_symtab; + mod->strtab = mod->core_strtab; #endif module_free(mod, mod->module_init); mod->module_init = NULL; -- cgit v1.1 From 26d052bfce799ef0e7262695b46e3525ca4d381d Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Mon, 6 Jul 2009 17:11:22 +0200 Subject: param: allow whitespace as kernel parameter separator Some boot mechanisms require that kernel parameters are stored in a separate file which is loaded to memory without further processing (e.g. the "Load from FTP" method on s390). When such a file contains newline characters, the kernel parameter preceding the newline might not be correctly parsed (due to the newline being stuck to the end of the actual parameter value) which can lead to boot failures. This patch improves kernel command line usability in such a situation by allowing generic whitespace characters as separators between kernel parameters. Signed-off-by: Peter Oberparleiter Signed-off-by: Rusty Russell --- kernel/params.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/params.c b/kernel/params.c index 7f6912c..9da58ea 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -23,6 +23,7 @@ #include #include #include +#include #if 0 #define DEBUGP printk @@ -87,7 +88,7 @@ static char *next_arg(char *args, char **param, char **val) } for (i = 0; args[i]; i++) { - if (args[i] == ' ' && !in_quote) + if (isspace(args[i]) && !in_quote) break; if (equals == 0) { if (args[i] == '=') @@ -121,7 +122,7 @@ static char *next_arg(char *args, char **param, char **val) next = args + i; /* Chew up trailing spaces. */ - while (*next == ' ') + while (isspace(*next)) next++; return next; } @@ -138,7 +139,7 @@ int parse_args(const char *name, DEBUGP("Parsing ARGS: %s\n", args); /* Chew leading spaces */ - while (*args == ' ') + while (isspace(*args)) args++; while (*args) { -- cgit v1.1 From a263f7763c364015f92e7c097fa46c6673f6fcb0 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Sep 2009 00:32:58 -0600 Subject: module: fix memory leak when load fails after srcversion/version allocated Normally the twisty paths of sysfs will free the attributes, but not if we fail before we hook it into sysfs (which is the last thing we do in load_module). (This sysfs code is a turd, no doubt there are other issues lurking too). Reported-by: Tetsuo Handa Signed-off-by: Rusty Russell Cc: Catalin Marinas Tested-by: Tetsuo Handa --- kernel/module.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index 39827c3..c54f10d 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1797,6 +1797,17 @@ static void setup_modinfo(struct module *mod, Elf_Shdr *sechdrs, } } +static void free_modinfo(struct module *mod) +{ + struct module_attribute *attr; + int i; + + for (i = 0; (attr = modinfo_attrs[i]); i++) { + if (attr->free) + attr->free(mod); + } +} + #ifdef CONFIG_KALLSYMS /* lookup symbol in given range of kernel_symbols */ @@ -2506,6 +2517,7 @@ static noinline struct module *load_module(void __user *umod, synchronize_sched(); module_arch_cleanup(mod); cleanup: + free_modinfo(mod); kobject_del(&mod->mkobj.kobj); kobject_put(&mod->mkobj.kobj); free_unload: -- cgit v1.1 From ffa9f12a41ec117207e8d953f90b9c179546c8d7 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 25 Sep 2009 00:32:59 -0600 Subject: module: don't call percpu_modfree on NULL pointer. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The general one handles NULL, the static obsolescent (CONFIG_HAVE_LEGACY_PER_CPU_AREA) one in module.c doesn't; Eric's commit 720eba31 assumed it did, and various frobbings since then kept that assumption. All other callers in module.c all protect it with an if; this effectively does the same as free_init is only goto if we fail percpu_modalloc(). Reported-by: Kamalesh Babulal Signed-off-by: Rusty Russell Cc: Eric Dumazet Cc: Masami Hiramatsu Cc: Américo Wang Tested-by: Kamalesh Babulal --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/module.c b/kernel/module.c index c54f10d..5a29397 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2523,8 +2523,8 @@ static noinline struct module *load_module(void __user *umod, free_unload: module_unload_free(mod); #if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP) - free_init: percpu_modfree(mod->refptr); + free_init: #endif module_free(mod, mod->module_init); free_core: -- cgit v1.1