releases/5.0.14/arm64-fix-wrong-check-of-on_sdei_stack-in-nmi-contex.patch

   1 From ecc9bccbd70ef9fc103e55719787d3c9d9b8f4d5 Mon Sep 17 00:00:00 2001
   2 From: Wei Li <liwei391@huawei.com>
   3 Date: Mon, 1 Apr 2019 11:55:57 +0800
   4 Subject: arm64: fix wrong check of on_sdei_stack in nmi context
   5
   6 [ Upstream commit 1c41860864c8ae0387ef7d44f0000e99cbb2e06d ]
   7
   8 When doing unwind_frame() in the context of pseudo nmi (need enable
   9 CONFIG_ARM64_PSEUDO_NMI), reaching the bottom of the stack (fp == 0,
  10 pc != 0), function on_sdei_stack() will return true while the sdei acpi
  11 table is not inited in fact. This will cause a "NULL pointer dereference"
  12 oops when going on.
  13
  14 Reviewed-by: Julien Thierry <julien.thierry@arm.com>
  15 Signed-off-by: Wei Li <liwei391@huawei.com>
  16 Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
  17 Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
  18 ---
  19  arch/arm64/kernel/sdei.c | 6 ++++++
  20  1 file changed, 6 insertions(+)
  21
  22 diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
  23 index 5ba4465e44f0..ea94cf8f9dc6 100644
  24 --- a/arch/arm64/kernel/sdei.c
  25 +++ b/arch/arm64/kernel/sdei.c
  26 @@ -94,6 +94,9 @@ static bool on_sdei_normal_stack(unsigned long sp, struct stack_info *info)
  27         unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
  28         unsigned long high = low + SDEI_STACK_SIZE;
  29
  30 +       if (!low)
  31 +               return false;
  32 +
  33         if (sp < low || sp >= high)
  34                 return false;
  35
  36 @@ -111,6 +114,9 @@ static bool on_sdei_critical_stack(unsigned long sp, struct stack_info *info)
  37         unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
  38         unsigned long high = low + SDEI_STACK_SIZE;
  39
  40 +       if (!low)
  41 +               return false;
  42 +
  43         if (sp < low || sp >= high)
  44                 return false;
  45
  46 --
  47 2.20.1
  48