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authorNathan Zimmer <nzimmer@sgi.com>2013-08-28 16:35:14 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-07 22:09:58 -0700
commitb3772c81e3490f1ddc0547ee479598f3f4221699 (patch)
tree65653cea05c7a68ea1f51177bb7bbfca19764402 /kernel/time
parentf1179e006ed4315834bdbf0982b40f7029cf0977 (diff)
downloadlinaro-lsk-b3772c81e3490f1ddc0547ee479598f3f4221699.tar.gz
timer_list: correct the iterator for timer_list
commit 84a78a6504f5c5394a8e558702e5b54131f01d14 upstream. Correct an issue with /proc/timer_list reported by Holger. When reading from the proc file with a sufficiently small buffer, 2k so not really that small, there was one could get hung trying to read the file a chunk at a time. The timer_list_start function failed to account for the possibility that the offset was adjusted outside the timer_list_next. Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Reported-by: Holger Hans Peter Freyther <holger@freyther.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Berke Durak <berke.durak@xiphos.com> Cc: Jeff Layton <jlayton@redhat.com> Tested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/timer_list.c41
1 files changed, 24 insertions, 17 deletions
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 3bdf2832301..61ed862cdd3 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -265,10 +265,9 @@ static inline void timer_list_header(struct seq_file *m, u64 now)
static int timer_list_show(struct seq_file *m, void *v)
{
struct timer_list_iter *iter = v;
- u64 now = ktime_to_ns(ktime_get());
if (iter->cpu == -1 && !iter->second_pass)
- timer_list_header(m, now);
+ timer_list_header(m, iter->now);
else if (!iter->second_pass)
print_cpu(m, iter->cpu, iter->now);
#ifdef CONFIG_GENERIC_CLOCKEVENTS
@@ -298,33 +297,41 @@ void sysrq_timer_list_show(void)
return;
}
-static void *timer_list_start(struct seq_file *file, loff_t *offset)
+static void *move_iter(struct timer_list_iter *iter, loff_t offset)
{
- struct timer_list_iter *iter = file->private;
-
- if (!*offset) {
- iter->cpu = -1;
- iter->now = ktime_to_ns(ktime_get());
- } else if (iter->cpu >= nr_cpu_ids) {
+ for (; offset; offset--) {
+ iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
+ if (iter->cpu >= nr_cpu_ids) {
#ifdef CONFIG_GENERIC_CLOCKEVENTS
- if (!iter->second_pass) {
- iter->cpu = -1;
- iter->second_pass = true;
- } else
- return NULL;
+ if (!iter->second_pass) {
+ iter->cpu = -1;
+ iter->second_pass = true;
+ } else
+ return NULL;
#else
- return NULL;
+ return NULL;
#endif
+ }
}
return iter;
}
+static void *timer_list_start(struct seq_file *file, loff_t *offset)
+{
+ struct timer_list_iter *iter = file->private;
+
+ if (!*offset)
+ iter->now = ktime_to_ns(ktime_get());
+ iter->cpu = -1;
+ iter->second_pass = false;
+ return move_iter(iter, *offset);
+}
+
static void *timer_list_next(struct seq_file *file, void *v, loff_t *offset)
{
struct timer_list_iter *iter = file->private;
- iter->cpu = cpumask_next(iter->cpu, cpu_online_mask);
++*offset;
- return timer_list_start(file, offset);
+ return move_iter(iter, 1);
}
static void timer_list_stop(struct seq_file *seq, void *v)