On 2016/09/14 18:25, zhong jiang wrote: > On 2016/9/14 16:52, Michal Hocko wrote: >> On Wed 14-09-16 10:42:19, Michal Hocko wrote: >>> [Let's CC Hugh] >> now for real... >> >>> On Wed 14-09-16 15:13:50, zhong jiang wrote: >>> [...] >>>> hi, Michal >>>> >>>> Recently, I hit the same issue when run a OOM case of the LTP and ksm enable. >>>> >>>> [ 601.937145] Call trace: >>>> [ 601.939600] [<ffffffc000086a88>] __switch_to+0x74/0x8c >>>> [ 601.944760] [<ffffffc000a1bae0>] __schedule+0x23c/0x7bc >>>> [ 601.950007] [<ffffffc000a1c09c>] schedule+0x3c/0x94 >>>> [ 601.954907] [<ffffffc000a1eb84>] rwsem_down_write_failed+0x214/0x350 >>>> [ 601.961289] [<ffffffc000a1e32c>] down_write+0x64/0x80 >>>> [ 601.966363] [<ffffffc00021f794>] __ksm_exit+0x90/0x19c >>>> [ 601.971523] [<ffffffc0000be650>] mmput+0x118/0x11c >>>> [ 601.976335] [<ffffffc0000c3ec4>] do_exit+0x2dc/0xa74 >>>> [ 601.981321] [<ffffffc0000c46f8>] do_group_exit+0x4c/0xe4 >>>> [ 601.986656] [<ffffffc0000d0f34>] get_signal+0x444/0x5e0 >>>> [ 601.991904] [<ffffffc000089fcc>] do_signal+0x1d8/0x450 >>>> [ 601.997065] [<ffffffc00008a35c>] do_notify_resume+0x70/0x78 Please be sure to include exact kernel version (e.g. "uname -r", "cat /proc/version") when reporting. You are reporting a bug in 4.1-stable kernel, which was prone to OOM livelock because the OOM reaper is not available. ( http://lkml.kernel.org/r/57D8012F.7080508@xxxxxxxxxx ) I think we no longer can reproduce this bug using 4.8-rc6 (or linux-next), but it will be a nice thing to backport __GFP_NORETRY patch to stable kernels which do not have the OOM reaper. > Adding the __GFP_NORETRY, the issue also can fixed. > Therefore, we can assure that the case of LTP will leads to the endless looping. > > index d45a0a1..03fb67b 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -283,7 +283,7 @@ static inline struct rmap_item *alloc_rmap_item(void) > { > struct rmap_item *rmap_item; > > - rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL); > + rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | __GFP_NORETRY); > if (rmap_item) > ksm_rmap_items++; > return rmap_item; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>