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Commit a5c43dae7ae38c2a6b3e9a819bcf45f010bf6a4a

Authored by Alexey Dobriyan
Committed by Linus Torvalds
1 parent 9d65cb4a17

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 <adobriyan@sw.ru>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 5 changed files with 61 additions and 7 deletions Side-by-side Diff

include/linux/kallsyms.h
Diff comments   View file @ a5c43da
... ... @@ -31,6 +31,7 @@
31 31 extern void __print_symbol(const char *fmt, unsigned long address);
32 32  
33 33 int lookup_symbol_name(unsigned long addr, char *symname);
  34 +int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
34 35  
35 36 #else /* !CONFIG_KALLSYMS */
36 37  
... ... @@ -61,6 +62,11 @@
61 62 }
62 63  
63 64 static inline int lookup_symbol_name(unsigned long addr, char *symname)
  65 +{
  66 + return -ERANGE;
  67 +}
  68 +
  69 +static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
64 70 {
65 71 return -ERANGE;
66 72 }
include/linux/module.h
Diff comments   View file @ a5c43da
... ... @@ -455,6 +455,7 @@
455 455 unsigned long *offset,
456 456 char **modname);
457 457 int lookup_module_symbol_name(unsigned long addr, char *symname);
  458 +int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
458 459  
459 460 /* For extable.c to search modules' exception tables. */
460 461 const struct exception_table_entry *search_module_extables(unsigned long addr);
... ... @@ -527,6 +528,11 @@
527 528 }
528 529  
529 530 static inline int lookup_module_symbol_name(unsigned long addr, char *symname)
  531 +{
  532 + return -ERANGE;
  533 +}
  534 +
  535 +static inline int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name)
530 536 {
531 537 return -ERANGE;
532 538 }
... ... @@ -286,6 +286,25 @@
286 286 return lookup_module_symbol_name(addr, symname);
287 287 }
288 288  
  289 +int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
  290 + unsigned long *offset, char *modname, char *name)
  291 +{
  292 + name[0] = '\0';
  293 + name[KSYM_NAME_LEN] = '\0';
  294 +
  295 + if (is_ksym_addr(addr)) {
  296 + unsigned long pos;
  297 +
  298 + pos = get_symbol_pos(addr, size, offset);
  299 + /* Grab name */
  300 + kallsyms_expand_symbol(get_symbol_offset(pos), name);
  301 + modname[0] = '\0';
  302 + return 0;
  303 + }
  304 + /* see if it's in a module */
  305 + return lookup_module_symbol_attrs(addr, size, offset, modname, name);
  306 +}
  307 +
289 308 /* Look up a kernel symbol and return it in a text buffer. */
290 309 int sprint_symbol(char *buffer, unsigned long address)
291 310 {
... ... @@ -2149,6 +2149,33 @@
2149 2149 return -ERANGE;
2150 2150 }
2151 2151  
  2152 +int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
  2153 + unsigned long *offset, char *modname, char *name)
  2154 +{
  2155 + struct module *mod;
  2156 +
  2157 + mutex_lock(&module_mutex);
  2158 + list_for_each_entry(mod, &modules, list) {
  2159 + if (within(addr, mod->module_init, mod->init_size) ||
  2160 + within(addr, mod->module_core, mod->core_size)) {
  2161 + const char *sym;
  2162 +
  2163 + sym = get_ksymbol(mod, addr, size, offset);
  2164 + if (!sym)
  2165 + goto out;
  2166 + if (modname)
  2167 + strlcpy(modname, mod->name, MODULE_NAME_LEN + 1);
  2168 + if (name)
  2169 + strlcpy(name, sym, KSYM_NAME_LEN + 1);
  2170 + mutex_unlock(&module_mutex);
  2171 + return 0;
  2172 + }
  2173 + }
  2174 +out:
  2175 + mutex_unlock(&module_mutex);
  2176 + return -ERANGE;
  2177 +}
  2178 +
2152 2179 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
2153 2180 char *name, char *module_name, int *exported)
2154 2181 {
... ... @@ -4432,16 +4432,12 @@
4432 4432 static void show_symbol(struct seq_file *m, unsigned long address)
4433 4433 {
4434 4434 #ifdef CONFIG_KALLSYMS
4435   - char *modname;
4436   - const char *name;
4437 4435 unsigned long offset, size;
4438   - char namebuf[KSYM_NAME_LEN+1];
  4436 + char modname[MODULE_NAME_LEN + 1], name[KSYM_NAME_LEN + 1];
4439 4437  
4440   - name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
4441   -
4442   - if (name) {
  4438 + if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4443 4439 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4444   - if (modname)
  4440 + if (modname[0])
4445 4441 seq_printf(m, " [%s]", modname);
4446 4442 return;
4447 4443 }