diff options
| author | Alexey Dobriyan <adobriyan@sw.ru> | 2007-05-08 09:28:43 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 20:15:08 +0200 |
| commit | 9d65cb4a1718a072898c7a57a3bc61b2dc4bcd4d (patch) | |
| tree | 9e3fd1c9e61e8ed16959d115a9a3f6f7eb0bbf21 /fs/proc | |
| parent | Simplify kallsyms_lookup() (diff) | |
| download | linux-9d65cb4a1718a072898c7a57a3bc61b2dc4bcd4d.tar.xz linux-9d65cb4a1718a072898c7a57a3bc61b2dc4bcd4d.zip | |
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')
| -rw-r--r-- | fs/proc/base.c | 11 |
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) */ static int proc_pid_wchan(struct task_struct *task, char *buffer) { - const char *sym_name; unsigned long wchan; - char namebuf[KSYM_NAME_LEN+1]; + char symname[KSYM_NAME_LEN+1]; wchan = get_wchan(task); - sym_name = kallsyms_lookup(wchan, NULL, NULL, NULL, namebuf); - if (sym_name) - return sprintf(buffer, "%s", sym_name); - return sprintf(buffer, "%lu", wchan); + if (lookup_symbol_name(wchan, symname) < 0) + return sprintf(buffer, "%lu", wchan); + else + return sprintf(buffer, "%s", symname); } #endif /* CONFIG_KALLSYMS */ |