target/linux/mpc85xx/patches-5.10/002-powerpc-85xx-fix-oops-when-CONFIG_FSL_PMC-n.patch

   1 From e7757563e621522f5cd862b3aff473aedf8b66c0 Mon Sep 17 00:00:00 2001
   2 From: Xiaoming Ni <nixiaoming@huawei.com>
   3 Date: Fri, 26 Nov 2021 12:11:53 +0800
   4 Subject: [PATCH] powerpc/85xx: fix oops when CONFIG_FSL_PMC=n
   5
   6 When CONFIG_FSL_PMC is set to n, no value is assigned to cpu_up_prepare
   7  in the mpc85xx_pm_ops structure. As a result, oops is triggered in
   8  smp_85xx_start_cpu().
   9
  10         [    0.627233] smp: Bringing up secondary CPUs ...
  11         [    0.681659] kernel tried to execute user page (0) - exploit attempt? (uid: 0)
  12         [    0.766618] BUG: Unable to handle kernel instruction fetch (NULL pointer?)
  13         [    0.848899] Faulting instruction address: 0x00000000
  14         [    0.908273] Oops: Kernel access of bad area, sig: 11 [#1]
  15         ...
  16         [    1.758220] NIP [00000000] 0x0
  17         [    1.794688] LR [c0021d2c] smp_85xx_kick_cpu+0xe8/0x568
  18         [    1.856126] Call Trace:
  19         [    1.885295] [c1051da8] [c0021cb8] smp_85xx_kick_cpu+0x74/0x568 (unreliable)
  20         [    1.968633] [c1051de8] [c0011460] __cpu_up+0xc0/0x228
  21         [    2.029038] [c1051e18] [c0031bbc] bringup_cpu+0x30/0x224
  22         [    2.092572] [c1051e48] [c0031f3c] cpu_up.constprop.0+0x180/0x33c
  23         [    2.164443] [c1051e88] [c00322e8] bringup_nonboot_cpus+0x88/0xc8
  24         [    2.236326] [c1051eb8] [c07e67bc] smp_init+0x30/0x78
  25         [    2.295698] [c1051ed8] [c07d9e28] kernel_init_freeable+0x118/0x2a8
  26         [    2.369641] [c1051f18] [c00032d8] kernel_init+0x14/0x124
  27         [    2.433176] [c1051f38] [c0010278] ret_from_kernel_thread+0x14/0x1c
  28
  29 Fixes: c45361abb9185b ("powerpc/85xx: fix timebase sync issue when
  30  CONFIG_HOTPLUG_CPU=n")
  31 Link: https://lore.kernel.org/lkml/CANA18Uyba4kMJQrbCSZVTFep2Exe5izE45whNJgwwUvNSEcNLg@mail.gmail.com/
  32 Reported-by: Martin Kennedy <hurricos@gmail.com>
  33 Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
  34 Tested-by: Martin Kennedy <hurricos@gmail.com>
  35 Cc: stable@vger.kernel.org
  36 --- a/arch/powerpc/platforms/85xx/smp.c
  37 +++ b/arch/powerpc/platforms/85xx/smp.c
  38 @@ -220,7 +220,7 @@ static int smp_85xx_start_cpu(int cpu)
  39         local_irq_save(flags);
  40         hard_irq_disable();
  41
  42 -       if (qoriq_pm_ops)
  43 +       if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
  44                 qoriq_pm_ops->cpu_up_prepare(cpu);
  45
  46         /* if cpu is not spinning, reset it */
  47 @@ -292,7 +292,7 @@ static int smp_85xx_kick_cpu(int nr)
  48                 booting_thread_hwid = cpu_thread_in_core(nr);
  49                 primary = cpu_first_thread_sibling(nr);
  50
  51 -               if (qoriq_pm_ops)
  52 +               if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
  53                         qoriq_pm_ops->cpu_up_prepare(nr);
  54
  55                 /*