+LKML I can not find the possibility when I check the code. because the mmap_sem and spin_lock will protect the concurrence. I will be appreciated if anyone has some clue. Thanks, zhong jiang On 2018/11/8 23:01, zhong jiang wrote: > Hi, > > Recently, I hit the following issue in linux 3.10 stable. and hard to recur. > > bad pmd ffff880c13ecea80(80000017b16000e7) > > Call Trace: > [<ffffffff8164195f>] dump_stack+0x19/0x1b > [<ffffffff8107b230>] warn_slowpath_common+0x70/0xb0 > [<ffffffff8107b37a>] warn_slowpath_null+0x1a/0x20 > [<ffffffff811a2b86>] exit_mmap+0x196/0x1a0 > [<ffffffff810782e7>] mmput+0x67/0xf0 > [<ffffffff81081b2c>] do_exit+0x28c/0xa60 > [<ffffffff810a9dc0>] ? hrtimer_get_res+0x50/0x50 > [<ffffffff8108237f>] do_group_exit+0x3f/0xa0 > [<ffffffff81093240>] get_signal_to_deliver+0x1d0/0x6d0 > [<ffffffff81014427>] do_signal+0x57/0x6b0 > [<ffffffff810e4f92>] ? futex_wait_queue_me+0xa2/0x120 > [<ffffffff8164d323>] ? __do_page_fault+0x183/0x470 > [<ffffffff81014adf>] do_notify_resume+0x5f/0xb0 > [<ffffffff816520bd>] int_signal+0x12/0x17 > > BUG: Bad rss-counter state mm:ffff8820136b5dc0 idx:1 val:512 > > The pmd entry show that it is still a thp. but It fails to check and clear the pmd. > hence, page fault will produce a new page for pmd when accessing the page, > which thp count will reduplicative increase. > > Thanks, > zhong jiang
