Commit 84a78a65 authored by Nathan Zimmer's avatar Nathan Zimmer Committed by Linus Torvalds
Browse files

timer_list: correct the iterator for timer_list



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: default avatarNathan Zimmer <nzimmer@sgi.com>
Reported-by: default avatarHolger 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: default avatarAl Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fa8218de
......@@ -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)
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment