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 <adobriyan@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2007-05-08 00:28:43 -07:00 committed by Linus Torvalds
parent ffb4512276
commit 9d65cb4a17
7 changed files with 66 additions and 19 deletions

View file

@ -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)