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authorAlexey Dobriyan <adobriyan@sw.ru>2007-05-08 03:28:43 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 14:15:08 -0400
commit9d65cb4a1718a072898c7a57a3bc61b2dc4bcd4d (patch)
tree9e3fd1c9e61e8ed16959d115a9a3f6f7eb0bbf21 /fs/proc/base.c
parentffb45122766db220d0bf3d01848d575fbbcb6430 (diff)
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>
Diffstat (limited to 'fs/proc/base.c')
-rw-r--r--fs/proc/base.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3b4fe21c7e94..0c2052c79243 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -278,16 +278,15 @@ static int proc_pid_auxv(struct task_struct *task, char *buffer)
278 */ 278 */
279static int proc_pid_wchan(struct task_struct *task, char *buffer) 279static int proc_pid_wchan(struct task_struct *task, char *buffer)
280{ 280{
281 const char *sym_name;
282 unsigned long wchan; 281 unsigned long wchan;
283 char namebuf[KSYM_NAME_LEN+1]; 282 char symname[KSYM_NAME_LEN+1];
284 283
285 wchan = get_wchan(task); 284 wchan = get_wchan(task);
286 285
287 sym_name = kallsyms_lookup(wchan, NULL, NULL, NULL, namebuf); 286 if (lookup_symbol_name(wchan, symname) < 0)
288 if (sym_name) 287 return sprintf(buffer, "%lu", wchan);
289 return sprintf(buffer, "%s", sym_name); 288 else
290 return sprintf(buffer, "%lu", wchan); 289 return sprintf(buffer, "%s", symname);
291} 290}
292#endif /* CONFIG_KALLSYMS */ 291#endif /* CONFIG_KALLSYMS */
293 292