From a5c43dae7ae38c2a6b3e9a819bcf45f010bf6a4a Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 8 May 2007 00:28:47 -0700 Subject: [PATCH] Fix race between cat /proc/slab_allocators and rmmod Same story as with cat /proc/*/wchan race vs rmmod race, only /proc/slab_allocators want more info than just symbol name. Signed-off-by: Alexey Dobriyan Acked-by: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kallsyms.h | 6 ++++++ include/linux/module.h | 6 ++++++ kernel/kallsyms.c | 19 +++++++++++++++++++ kernel/module.c | 27 +++++++++++++++++++++++++++ mm/slab.c | 10 +++------- 5 files changed, 61 insertions(+), 7 deletions(-) diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index ae0117a95cfd..12178d2c882b 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -31,6 +31,7 @@ extern int sprint_symbol(char *buffer, unsigned long address); extern void __print_symbol(const char *fmt, unsigned long address); int lookup_symbol_name(unsigned long addr, char *symname); +int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name); #else /* !CONFIG_KALLSYMS */ @@ -65,6 +66,11 @@ static inline int lookup_symbol_name(unsigned long addr, char *symname) return -ERANGE; } +static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name) +{ + return -ERANGE; +} + /* Stupid that this does nothing, but I didn't create this mess. */ #define __print_symbol(fmt, addr) #endif /*CONFIG_KALLSYMS*/ diff --git a/include/linux/module.h b/include/linux/module.h index 099ae5932c68..6d3dc9c4ff96 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -455,6 +455,7 @@ const char *module_address_lookup(unsigned long addr, unsigned long *offset, char **modname); int lookup_module_symbol_name(unsigned long addr, char *symname); +int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name); /* For extable.c to search modules' exception tables. */ const struct exception_table_entry *search_module_extables(unsigned long addr); @@ -531,6 +532,11 @@ static inline int lookup_module_symbol_name(unsigned long addr, char *symname) return -ERANGE; } +static inline int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name) +{ + return -ERANGE; +} + static inline int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 4e2ec191a127..c36581b40c04 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -286,6 +286,25 @@ int lookup_symbol_name(unsigned long addr, char *symname) return lookup_module_symbol_name(addr, symname); } +int lookup_symbol_attrs(unsigned long addr, unsigned long *size, + unsigned long *offset, char *modname, char *name) +{ + name[0] = '\0'; + name[KSYM_NAME_LEN] = '\0'; + + if (is_ksym_addr(addr)) { + unsigned long pos; + + pos = get_symbol_pos(addr, size, offset); + /* Grab name */ + kallsyms_expand_symbol(get_symbol_offset(pos), name); + modname[0] = '\0'; + return 0; + } + /* see if it's in a module */ + return lookup_module_symbol_attrs(addr, size, offset, modname, name); +} + /* Look up a kernel symbol and return it in a text buffer. */ int sprint_symbol(char *buffer, unsigned long address) { diff --git a/kernel/module.c b/kernel/module.c index 3da76ad32d78..d36e45477fac 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2149,6 +2149,33 @@ out: return -ERANGE; } +int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, + unsigned long *offset, char *modname, char *name) +{ + struct module *mod; + + mutex_lock(&module_mutex); + list_for_each_entry(mod, &modules, list) { + if (within(addr, mod->module_init, mod->init_size) || + within(addr, mod->module_core, mod->core_size)) { + const char *sym; + + sym = get_ksymbol(mod, addr, size, offset); + if (!sym) + goto out; + if (modname) + strlcpy(modname, mod->name, MODULE_NAME_LEN + 1); + if (name) + strlcpy(name, sym, KSYM_NAME_LEN + 1); + mutex_unlock(&module_mutex); + return 0; + } + } +out: + mutex_unlock(&module_mutex); + return -ERANGE; +} + int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) { diff --git a/mm/slab.c b/mm/slab.c index 1115e2065bfc..acda7e2d66e4 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4432,16 +4432,12 @@ static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) static void show_symbol(struct seq_file *m, unsigned long address) { #ifdef CONFIG_KALLSYMS - char *modname; - const char *name; unsigned long offset, size; - char namebuf[KSYM_NAME_LEN+1]; - - name = kallsyms_lookup(address, &size, &offset, &modname, namebuf); + char modname[MODULE_NAME_LEN + 1], name[KSYM_NAME_LEN + 1]; - if (name) { + if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) { seq_printf(m, "%s+%#lx/%#lx", name, offset, size); - if (modname) + if (modname[0]) seq_printf(m, " [%s]", modname); return; } -- 2.34.1