git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From e75d18cecbb3805895d8ed64da4f78575ec96043 Mon Sep 17 00:00:00 2001
   2 From: Sudeep Holla <sudeep.holla@arm.com>
   3 Date: Mon, 8 Aug 2022 09:46:40 +0100
   4 Subject: arm64: cacheinfo: Fix incorrect assignment of signed error value to unsigned fw_level
   5
   6 From: Sudeep Holla <sudeep.holla@arm.com>
   7
   8 commit e75d18cecbb3805895d8ed64da4f78575ec96043 upstream.
   9
  10 Though acpi_find_last_cache_level() always returned signed value and the
  11 document states it will return any errors caused by lack of a PPTT table,
  12 it never returned negative values before.
  13
  14 Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage")
  15 however changed it by returning -ENOENT if no PPTT was found. The value
  16 returned from acpi_find_last_cache_level() is then assigned to unsigned
  17 fw_level.
  18
  19 It will result in the number of cache leaves calculated incorrectly as
  20 a huge value which will then cause the following warning from __alloc_pages
  21 as the order would be great than MAX_ORDER because of incorrect and huge
  22 cache leaves value.
  23
  24   |  WARNING: CPU: 0 PID: 1 at mm/page_alloc.c:5407 __alloc_pages+0x74/0x314
  25   |  Modules linked in:
  26   |  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-10393-g7c2a8d3ac4c0 #73
  27   |  pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  28   |  pc : __alloc_pages+0x74/0x314
  29   |  lr : alloc_pages+0xe8/0x318
  30   |  Call trace:
  31   |   __alloc_pages+0x74/0x314
  32   |   alloc_pages+0xe8/0x318
  33   |   kmalloc_order_trace+0x68/0x1dc
  34   |   __kmalloc+0x240/0x338
  35   |   detect_cache_attributes+0xe0/0x56c
  36   |   update_siblings_masks+0x38/0x284
  37   |   store_cpu_topology+0x78/0x84
  38   |   smp_prepare_cpus+0x48/0x134
  39   |   kernel_init_freeable+0xc4/0x14c
  40   |   kernel_init+0x2c/0x1b4
  41   |   ret_from_fork+0x10/0x20
  42
  43 Fix the same by changing fw_level to be signed integer and return the
  44 error from init_cache_level() early in case of error.
  45
  46 Reported-and-Tested-by: Bruno Goncalves <bgoncalv@redhat.com>
  47 Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
  48 Link: https://lore.kernel.org/r/20220808084640.3165368-1-sudeep.holla@arm.com
  49 Signed-off-by: Will Deacon <will@kernel.org>
  50 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  51 ---
  52  arch/arm64/kernel/cacheinfo.c |    6 +++++-
  53  1 file changed, 5 insertions(+), 1 deletion(-)
  54
  55 --- a/arch/arm64/kernel/cacheinfo.c
  56 +++ b/arch/arm64/kernel/cacheinfo.c
  57 @@ -45,7 +45,8 @@ static void ci_leaf_init(struct cacheinf
  58
  59  int init_cache_level(unsigned int cpu)
  60  {
  61 -       unsigned int ctype, level, leaves, fw_level;
  62 +       unsigned int ctype, level, leaves;
  63 +       int fw_level;
  64         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  65
  66         for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
  67 @@ -63,6 +64,9 @@ int init_cache_level(unsigned int cpu)
  68         else
  69                 fw_level = acpi_find_last_cache_level(cpu);
  70
  71 +       if (fw_level < 0)
  72 +               return fw_level;
  73 +
  74         if (level < fw_level) {
  75                 /*
  76                  * some external caches not specified in CLIDR_EL1