On Fri, Sep 7, 2018 at 1:23 PM, Tetsuo Handa
<penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote:
> syzbot is getting stalls with linux-next kernels because dump_tasks() from
> out_of_memory() is printing 6600 tasks. Most of these tasks are syzbot
> processes but syzbot is supposed not to create so many processes.
> Therefore, let's start from checking what these tasks are doing.
> This change will be removed after the bug is fixed.
>
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxxxx>
> ---
> mm/oom_kill.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index f10aa53..867fd6a 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -41,6 +41,7 @@
> #include <linux/kthread.h>
> #include <linux/init.h>
> #include <linux/mmu_notifier.h>
> +#include <linux/sched/debug.h>
>
> #include <asm/tlb.h>
> #include "internal.h"
> @@ -446,6 +447,10 @@ static void dump_header(struct oom_control *oc, struct task_struct *p)
> if (is_dump_unreclaim_slabs())
> dump_unreclaimable_slab();
> }
> +#ifdef CONFIG_DEBUG_AID_FOR_SYZBOT
> + show_state();
> + panic("Out of memory");
won't this panic on every oom?
we have lots of oom's, especially inside of cgroups, but probably global too
it would be bad if we crash all machines this way
> +#endif
> if (sysctl_oom_dump_tasks)
> dump_tasks(oc->memcg, oc->nodemask);
> }
> --
> 1.8.3.1
>
