2013/2/6 Stanislaw Gruszka <sgrus...@redhat.com>:
> Below is proposed fix. Error cases wasn't that bad since there are
> various limitations when timer could be fired (i.e. timer which
> already fired can not be fired again).
>
> Tommi, please check if patch really fixes the problem. I tested it
> with signal interrupt and timeout scenarios, but I don't know how
> to confirm if it fix the leak or not.
Hi, looks good, this patch fixes the leaks I'm seeing.
Without the patch, running the program from my earlier mail shows
task_struct count growing:
{ttrantal@arkki ~}> uname -r
3.8.0-rc6+
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 93 123 8880 3 8 : tunables 0 0
0 : slabdata 41 41 0
{ttrantal@arkki ~}> for i in `seq 1000` ; do ./leak ; done
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 1089 1089 8880 3 8 : tunables 0 0
0 : slabdata 363 363 0
{ttrantal@arkki ~}> for i in `seq 1000` ; do ./leak ; done
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 2088 2088 8880 3 8 : tunables 0 0
0 : slabdata 696 696 0
{ttrantal@arkki ~}>
With the patch applied, the leak is gone:
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 92 108 8880 3 8 : tunables 0 0
0 : slabdata 36 36 0
{ttrantal@arkki ~}> for i in `seq 1000` ; do ./leak ; done
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 92 108 8880 3 8 : tunables 0 0
0 : slabdata 36 36 0
{ttrantal@arkki ~}> for i in `seq 1000` ; do ./leak ; done
{ttrantal@arkki ~}> sudo grep task_struct /proc/slabinfo
task_struct 92 108 8880 3 8 : tunables 0 0
0 : slabdata 36 36 0
{ttrantal@arkki ~}>
Running Trinity with kmemleak enabled also resulted to a lot of
detected leaks, which are all gone now based on a quick run.
> diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
> index 125cb67..07a38b6 100644
> --- a/kernel/posix-cpu-timers.c
> +++ b/kernel/posix-cpu-timers.c
> @@ -1424,6 +1424,7 @@ static int do_cpu_nanosleep(const clockid_t
> which_clock, int flags,
> /*
> * Our timer fired and was reset.
> */
> + posix_cpu_timer_del(&timer);
> spin_unlock_irq(&timer.it_lock);
> return 0;
> }
> @@ -1441,9 +1442,17 @@ static int do_cpu_nanosleep(const clockid_t
> which_clock, int flags,
> * We were interrupted by a signal.
> */
> sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
> - posix_cpu_timer_set(&timer, 0, &zero_it, it);
> + error = posix_cpu_timer_set(&timer, 0, &zero_it, it);
> + if (!error)
> + posix_cpu_timer_del(&timer);
> spin_unlock_irq(&timer.it_lock);
>
> + while (error == TIMER_RETRY) {
> + spin_lock_irq(&timer.it_lock);
> + error = posix_cpu_timer_del(&timer);
> + spin_unlock_irq(&timer.it_lock);
> + }
> +
> if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
> /*
> * It actually did fire already.
--
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