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>
This commit is contained in:
Alexey Dobriyan
2007-05-08 00:28:43 -07:00
committed by Linus Torvalds
parent ffb4512276
commit 9d65cb4a17
7 changed files with 66 additions and 19 deletions

View File

@@ -38,15 +38,12 @@ DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
static void print_name_offset(struct seq_file *m, void *sym)
{
unsigned long addr = (unsigned long)sym;
char namebuf[KSYM_NAME_LEN+1];
const char *sym_name;
char symname[KSYM_NAME_LEN+1];
sym_name = kallsyms_lookup(addr, NULL, NULL, NULL, namebuf);
if (sym_name)
SEQ_printf(m, "%s", sym_name);
else
if (lookup_symbol_name((unsigned long)sym, symname) < 0)
SEQ_printf(m, "<%p>", sym);
else
SEQ_printf(m, "%s", symname);
}
static void