1. 13 1月, 2016 36 次提交
  2. 11 1月, 2016 1 次提交
  3. 10 1月, 2016 2 次提交
  4. 09 1月, 2016 1 次提交
    • M
      vmstat: allocate vmstat_wq before it is used · 751e5f5c
      Michal Hocko 提交于
      kernel test robot has reported the following crash:
      
        BUG: unable to handle kernel NULL pointer dereference at 00000100
        IP: [<c1074df6>] __queue_work+0x26/0x390
        *pdpt = 0000000000000000 *pde = f000ff53f000ff53 *pde = f000ff53f000ff53
        Oops: 0000 [#1] PREEMPT PREEMPT SMP SMP
        CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.4.0-rc4-00139-g373ccbe5 #1
        Workqueue: events vmstat_shepherd
        task: cb684600 ti: cb7ba000 task.ti: cb7ba000
        EIP: 0060:[<c1074df6>] EFLAGS: 00010046 CPU: 0
        EIP is at __queue_work+0x26/0x390
        EAX: 00000046 EBX: cbb37800 ECX: cbb37800 EDX: 00000000
        ESI: 00000000 EDI: 00000000 EBP: cb7bbe68 ESP: cb7bbe38
         DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
        CR0: 8005003b CR2: 00000100 CR3: 01fd5000 CR4: 000006b0
        Stack:
        Call Trace:
          __queue_delayed_work+0xa1/0x160
          queue_delayed_work_on+0x36/0x60
          vmstat_shepherd+0xad/0xf0
          process_one_work+0x1aa/0x4c0
          worker_thread+0x41/0x440
          kthread+0xb0/0xd0
          ret_from_kernel_thread+0x21/0x40
      
      The reason is that start_shepherd_timer schedules the shepherd work item
      which uses vmstat_wq (vmstat_shepherd) before setup_vmstat allocates
      that workqueue so if the further initialization takes more than HZ we
      might end up scheduling on a NULL vmstat_wq.  This is really unlikely
      but not impossible.
      
      Fixes: 373ccbe5 ("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress")
      Reported-by: Nkernel test robot <ying.huang@linux.intel.com>
      Signed-off-by: NMichal Hocko <mhocko@suse.com>
      Tested-by: NTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
      Cc: stable@vger.kernel.org
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      751e5f5c
新手
引导
客服 返回
顶部