Messages in this thread Patch in this message |  | | Date | Wed, 6 Feb 2013 14:01:21 +0200 | Subject | Re: clock_nanosleep() task_struct leak | From | Tommi Rantala <> |
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2013/2/6 Stanislaw Gruszka <sgruszka@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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