From 9d65cb4a1718a072898c7a57a3bc61b2dc4bcd4d Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 8 May 2007 00:28:43 -0700 Subject: Fix race between cat /proc/*/wchan and rmmod et al kallsyms_lookup() can go iterating over modules list unprotected which is OK for emergency situations (oops), but not OK for regular stuff like /proc/*/wchan. Introduce lookup_symbol_name()/lookup_module_symbol_name() which copy symbol name into caller-supplied buffer or return -ERANGE. All copying is done with module_mutex held, so... Signed-off-by: Alexey Dobriyan Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kallsyms.h | 7 +++++++ include/linux/module.h | 6 ++++++ 2 files changed, 13 insertions(+) (limited to 'include') diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index 3e3b92dabe3b..ae0117a95cfd 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -30,6 +30,8 @@ extern int sprint_symbol(char *buffer, unsigned long address); /* Look up a kernel symbol and print it to the kernel messages. */ extern void __print_symbol(const char *fmt, unsigned long address); +int lookup_symbol_name(unsigned long addr, char *symname); + #else /* !CONFIG_KALLSYMS */ static inline unsigned long kallsyms_lookup_name(const char *name) @@ -58,6 +60,11 @@ static inline int sprint_symbol(char *buffer, unsigned long addr) return 0; } +static inline int lookup_symbol_name(unsigned long addr, char *symname) +{ + 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 58d5a10cdf0d..099ae5932c68 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -454,6 +454,7 @@ const char *module_address_lookup(unsigned long addr, unsigned long *symbolsize, unsigned long *offset, char **modname); +int lookup_module_symbol_name(unsigned long addr, char *symname); /* For extable.c to search modules' exception tables. */ const struct exception_table_entry *search_module_extables(unsigned long addr); @@ -525,6 +526,11 @@ static inline const char *module_address_lookup(unsigned long addr, return NULL; } +static inline int lookup_module_symbol_name(unsigned long addr, char *symname) +{ + return -ERANGE; +} + static inline int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) -- cgit v1.2.3