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Fix race between cat /proc/*/wchan and rmmod et al

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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
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10
kernel/time/timer_stats.c
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@@ -257,14 +257,12 @@ void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
static void print_name_offset(struct seq_file *m, unsigned long addr)
{
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(addr, symname) < 0)
seq_printf(m, "<%p>", (void *)addr);
else
seq_printf(m, "%s", symname);
}
static int tstats_show(struct seq_file *m, void *v)