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Commit a5c43dae authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
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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: default avatarAlexey Dobriyan <adobriyan@sw.ru>
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9d65cb4a

include/linux/kallsyms.h

+6 −0
Original line number Diff line number Diff line
@@ -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*/

include/linux/module.h

+6 −0
Original line number Diff line number Diff line
@@ -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)

kernel/kallsyms.c

+19 −0
Original line number Diff line number Diff line
@@ -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)

{

kernel/module.c

+27 −0
Original line number Diff line number Diff line
@@ -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)

{

mm/slab.c

+3 −7
Original line number Diff line number Diff line
@@ -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;

	}