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KSYM_SYMBOL_LEN fixes

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Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked
to my 966c8c12dc sprint_symbol(): use
less stack exposing a bug in slub's list_locations() -
kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was
beyond the end of page provided.

The 100 slop which list_locations() allows at end of page looks roughly
enough for all the other stuff it might print after the symbol before
it checks again: break out KSYM_SYMBOL_LEN earlier than before.

Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they
need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer
where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies
them.

[akpm@linux-foundation.org: ftrace.h needs module.h]
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc Miles Lane <miles.lane@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
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:
Hugh Dickins 2008-12-09 13:14:27 -08:00 committed by Linus Torvalds
parent 6ee5a399d6
commit 9c24624727
5 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/proc/base.c
View File

@ -371,7 +371,7 @@ static int lstats_show_proc(struct seq_file *m, void *v)
task->latency_record[i].time,
task->latency_record[i].max);
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
char sym[KSYM_NAME_LEN];
char sym[KSYM_SYMBOL_LEN];
char *c;
if (!task->latency_record[i].backtrace[q])
break;

3
include/linux/ftrace.h
View File

@ -6,6 +6,7 @@
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#ifdef CONFIG_FUNCTION_TRACER
@ -231,7 +232,7 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }
struct boot_trace {
pid_t caller;
char func[KSYM_NAME_LEN];
char func[KSYM_SYMBOL_LEN];
int result;
unsigned long long duration; /* usecs */
ktime_t calltime;

2
kernel/latencytop.c
View File

@ -191,7 +191,7 @@ static int lstats_show(struct seq_file *m, void *v)
latency_record[i].time,
latency_record[i].max);
for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
char sym[KSYM_NAME_LEN];
char sym[KSYM_SYMBOL_LEN];
char *c;
if (!latency_record[i].backtrace[q])
break;

2
mm/slub.c
View File

@ -3597,7 +3597,7 @@ static int list_locations(struct kmem_cache *s, char *buf,
for (i = 0; i < t.count; i++) {
struct location *l = &t.loc[i];
if (len > PAGE_SIZE - 100)
if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
break;
len += sprintf(buf + len, "%7ld ", l->count);

2
mm/vmalloc.c
View File

@ -1717,7 +1717,7 @@ static int s_show(struct seq_file *m, void *p)
v->addr, v->addr + v->size, v->size);
if (v->caller) {
char buff[2 * KSYM_NAME_LEN];
char buff[KSYM_SYMBOL_LEN];
seq_putc(m, ' ');
sprint_symbol(buff, (unsigned long)v->caller);