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authorRusty Russell <rusty@rustcorp.com.au>2008-01-29 17:13:22 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-01-29 01:13:23 -0500
commit6dd06c9fbe025f542bce4cdb91790c0f91962722 (patch)
tree5c946eb93f30c64fd435bdd6d1064880ef21557a /kernel
parentbb9d3d56e792d2619cc0903df4ac01d86ac1261d (diff)
module: make module_address_lookup safe
module_address_lookup releases preemption then returns a pointer into the module space. The only user (kallsyms) copies the result, so just do that under the preempt disable. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kallsyms.c11
-rw-r--r--kernel/module.c22
2 files changed, 17 insertions, 16 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 2fc25810509e..7dadc71ce516 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -233,10 +233,11 @@ static unsigned long get_symbol_pos(unsigned long addr,
233int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize, 233int kallsyms_lookup_size_offset(unsigned long addr, unsigned long *symbolsize,
234 unsigned long *offset) 234 unsigned long *offset)
235{ 235{
236 char namebuf[KSYM_NAME_LEN];
236 if (is_ksym_addr(addr)) 237 if (is_ksym_addr(addr))
237 return !!get_symbol_pos(addr, symbolsize, offset); 238 return !!get_symbol_pos(addr, symbolsize, offset);
238 239
239 return !!module_address_lookup(addr, symbolsize, offset, NULL); 240 return !!module_address_lookup(addr, symbolsize, offset, NULL, namebuf);
240} 241}
241 242
242/* 243/*
@@ -251,8 +252,6 @@ const char *kallsyms_lookup(unsigned long addr,
251 unsigned long *offset, 252 unsigned long *offset,
252 char **modname, char *namebuf) 253 char **modname, char *namebuf)
253{ 254{
254 const char *msym;
255
256 namebuf[KSYM_NAME_LEN - 1] = 0; 255 namebuf[KSYM_NAME_LEN - 1] = 0;
257 namebuf[0] = 0; 256 namebuf[0] = 0;
258 257
@@ -268,10 +267,8 @@ const char *kallsyms_lookup(unsigned long addr,
268 } 267 }
269 268
270 /* see if it's in a module */ 269 /* see if it's in a module */
271 msym = module_address_lookup(addr, symbolsize, offset, modname); 270 return module_address_lookup(addr, symbolsize, offset, modname,
272 if (msym) 271 namebuf);
273 return strncpy(namebuf, msym, KSYM_NAME_LEN - 1);
274
275 return NULL; 272 return NULL;
276} 273}
277 274
diff --git a/kernel/module.c b/kernel/module.c
index 12067ff34d01..e814cd7da634 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2230,14 +2230,13 @@ static const char *get_ksymbol(struct module *mod,
2230 return mod->strtab + mod->symtab[best].st_name; 2230 return mod->strtab + mod->symtab[best].st_name;
2231} 2231}
2232 2232
2233/* For kallsyms to ask for address resolution. NULL means not found. 2233/* For kallsyms to ask for address resolution. NULL means not found. Careful
2234 We don't lock, as this is used for oops resolution and races are a 2234 * not to lock to avoid deadlock on oopses, simply disable preemption. */
2235 lesser concern. */ 2235char *module_address_lookup(unsigned long addr,
2236/* FIXME: Risky: returns a pointer into a module w/o lock */ 2236 unsigned long *size,
2237const char *module_address_lookup(unsigned long addr, 2237 unsigned long *offset,
2238 unsigned long *size, 2238 char **modname,
2239 unsigned long *offset, 2239 char *namebuf)
2240 char **modname)
2241{ 2240{
2242 struct module *mod; 2241 struct module *mod;
2243 const char *ret = NULL; 2242 const char *ret = NULL;
@@ -2252,8 +2251,13 @@ const char *module_address_lookup(unsigned long addr,
2252 break; 2251 break;
2253 } 2252 }
2254 } 2253 }
2254 /* Make a copy in here where it's safe */
2255 if (ret) {
2256 strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
2257 ret = namebuf;
2258 }
2255 preempt_enable(); 2259 preempt_enable();
2256 return ret; 2260 return (char *)ret;
2257} 2261}
2258 2262
2259int lookup_module_symbol_name(unsigned long addr, char *symname) 2263int lookup_module_symbol_name(unsigned long addr, char *symname)