RHEL7.5 上带有 qla2xxx 驱动程序的 get_next_timer_interrupt() 中的 NULL 指针

Issue

• 由于 NULL 指针取消引用，内核在 get_next_timer_interrupt() 中 panic :

  [1250992.394968] BUG: unable to handle kernel NULL pointer dereference at 0000000000000019
  [1250992.395774] IP: [<ffffffff91aa4e58>] get_next_timer_interrupt+0x1b8/0x260
  [1250992.396305] PGD 0 
  [1250992.396705] Oops: 0000 [#1] SMP 
  [1250992.402975] RIP: 0010:[<ffffffff91aa4e58>]  [<ffffffff91aa4e58>] get_next_timer_interrupt+0x1b8/0x260
  [1250992.409880] Call Trace:
  [1250992.410618]  [<ffffffff91b01f98>] tick_nohz_stop_sched_tick+0x1e8/0x380
  [1250992.411374]  [<ffffffff91b021cf>] __tick_nohz_idle_enter+0x9f/0x160
  [1250992.412084]  [<ffffffff91b0270f>] tick_nohz_idle_enter+0x3f/0x70
  [1250992.412799]  [<ffffffff91af32b7>] cpu_startup_entry+0xa7/0x1e0
  [1250992.413546]  [<ffffffff91a55f97>] start_secondary+0x1f7/0x270
  [1250992.414305]  [<ffffffff91a000d5>] start_cpu+0x5/0x14
  [1250992.416640] RIP  [<ffffffff91aa4e58>] get_next_timer_interrupt+0x1b8/0x260
  [1250992.417443]  RSP <ffff9a556766fdf0>
  [1250992.418239] CR2: 0000000000000019
  

• 其他日志模式如下：

  [    5.376055] Call Trace:
  [    5.378491]  <IRQ>  [<ffffffff90d54638>] dump_stack+0x19/0x1b
  [    5.384235]  [<ffffffff90696278>] __warn+0xd8/0x100
  [    5.389100]  [<ffffffff906963bd>] warn_slowpath_null+0x1d/0x20
  [    5.394918]  [<ffffffff906560f5>] native_smp_send_reschedule+0x65/0x70
  [    5.401430]  [<ffffffff906e39a1>] trigger_load_balance+0x191/0x280
  [    5.407595]  [<ffffffff906d2eca>] scheduler_tick+0x10a/0x150
  [    5.413241]  [<ffffffff90708e60>] ? tick_sched_do_timer+0x50/0x50
  [    5.419320]  [<ffffffff906a9825>] update_process_times+0x65/0x80
  [    5.425311]  [<ffffffff90708c60>] tick_sched_handle+0x30/0x70
  [    5.431043]  [<ffffffff90708e99>] tick_sched_timer+0x39/0x80
  [    5.436689]  [<ffffffff906c4286>] __hrtimer_run_queues+0xd6/0x260
  [    5.442767]  [<ffffffff906c481f>] hrtimer_interrupt+0xaf/0x1d0
  [    5.448586]  [<ffffffff9065974b>] local_apic_timer_interrupt+0x3b/0x60
  [    5.455098]  [<ffffffff90d6c9c3>] smp_apic_timer_interrupt+0x43/0x60
  [    5.461436]  [<ffffffff90d68d5c>] apic_timer_interrupt+0x17c/0x190
  [    5.467600]  <EOI>  [<ffffffff90d4df2d>] ? panic+0x1d5/0x21f
  [    5.473257]  [<ffffffff90d4de91>] ? panic+0x139/0x21f
  [    5.478295]  [<ffffffff90d5f7b5>] oops_end+0xc5/0xe0
  [    5.483248]  [<ffffffff90d4d36e>] no_context+0x285/0x2a8
  [    5.488546]  [<ffffffff90d4d405>] __bad_area_nosemaphore+0x74/0x1d1
  [    5.494797]  [<ffffffff90d4d576>] bad_area_nosemaphore+0x14/0x16
  [    5.500788]  [<ffffffff90d62750>] __do_page_fault+0x330/0x4f0
  [    5.506520]  [<ffffffff90d5a04c>] ? __schedule+0x41c/0xa20
  [    5.511992]  [<ffffffff90d62945>] do_page_fault+0x35/0x90
  [    5.517377]  [<ffffffff90d5e788>] page_fault+0x28/0x30
  [    5.522515]  [<ffffffffc06859ae>] ? __qla2x00_alloc_iocbs+0x12e/0x330 [qla2xxx]
  [    5.529818]  [<ffffffffc0685c0b>] __qla2x00_marker.isra.21+0x5b/0x140 [qla2xxx]
  [    5.537122]  [<ffffffffc0685d35>] qla2x00_marker+0x45/0x70 [qla2xxx]
  [    5.543471]  [<ffffffffc0670e79>] qla2x00_loop_resync+0x289/0x12a0 [qla2xxx]
  [    5.550504]  [<ffffffff906df0ce>] ? dequeue_task_fair+0x41e/0x660
  [    5.556580]  [<ffffffff9062a59e>] ? __switch_to+0xce/0x580
  [    5.562053]  [<ffffffff90d5a04c>] ? __schedule+0x41c/0xa20
  [    5.567523]  [<ffffffff906d051e>] ? set_user_nice+0x18e/0x250
  [    5.573264]  [<ffffffffc065ea65>] qla2x00_do_dpc+0x895/0xa20 [qla2xxx]
  [    5.579785]  [<ffffffffc065e1d0>] ? qla24xx_post_relogin_work+0x40/0x40 [qla2xxx]
  [    5.587250]  [<ffffffff906c00c1>] kthread+0xd1/0xe0
  [    5.592114]  [<ffffffff906bfff0>] ? insert_kthread_work+0x40/0x40
  [    5.598194]  [<ffffffff90d67b37>] ret_from_fork_nospec_begin+0x21/0x21
  [    5.604704]  [<ffffffff906bfff0>] ? insert_kthread_work+0x40/0x40