releases/5.0.4/acpi-device_sysfs-avoid-of-modalias-creation-for-removed-device.patch

   1 From f16eb8a4b096514ac06fb25bf599dcc792899b3d Mon Sep 17 00:00:00 2001
   2 From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
   3 Date: Mon, 11 Mar 2019 18:41:03 +0200
   4 Subject: ACPI / device_sysfs: Avoid OF modalias creation for removed device
   5
   6 From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
   7
   8 commit f16eb8a4b096514ac06fb25bf599dcc792899b3d upstream.
   9
  10 If SSDT overlay is loaded via ConfigFS and then unloaded the device,
  11 we would like to have OF modalias for, already gone. Thus, acpi_get_name()
  12 returns no allocated buffer for such case and kernel crashes afterwards:
  13
  14  ACPI: Host-directed Dynamic ACPI Table Unload
  15  ads7950 spi-PRP0001:00: Dropping the link to regulator.0
  16  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  17  #PF error: [normal kernel read fault]
  18  PGD 80000000070d6067 P4D 80000000070d6067 PUD 70d0067 PMD 0
  19  Oops: 0000 [#1] SMP PTI
  20  CPU: 0 PID: 40 Comm: kworker/u4:2 Not tainted 5.0.0+ #96
  21  Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
  22  Workqueue: kacpi_hotplug acpi_device_del_work_fn
  23  RIP: 0010:create_of_modalias.isra.1+0x4c/0x150
  24  Code: 00 00 48 89 44 24 18 31 c0 48 8d 54 24 08 48 c7 44 24 10 00 00 00 00 48 c7 44 24 08 ff ff ff ff e8 7a b0 03 00 48 8b 4c 24 10 <0f> b6 01 84 c0 74 27 48 c7 c7 00 09 f4 a5 0f b6 f0 8d 50 20 f6 04
  25  RSP: 0000:ffffa51040297c10 EFLAGS: 00010246
  26  RAX: 0000000000001001 RBX: 0000000000000785 RCX: 0000000000000000
  27  RDX: 0000000000001001 RSI: 0000000000000286 RDI: ffffa2163dc042e0
  28  RBP: ffffa216062b1196 R08: 0000000000001001 R09: ffffa21639873000
  29  R10: ffffffffa606761d R11: 0000000000000001 R12: ffffa21639873218
  30  R13: ffffa2163deb5060 R14: ffffa216063d1010 R15: 0000000000000000
  31  FS:  0000000000000000(0000) GS:ffffa2163e000000(0000) knlGS:0000000000000000
  32  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  33  CR2: 0000000000000000 CR3: 0000000007114000 CR4: 00000000001006f0
  34  Call Trace:
  35   __acpi_device_uevent_modalias+0xb0/0x100
  36   spi_uevent+0xd/0x40
  37
  38  ...
  39
  40 In order to fix above let create_of_modalias() check the status returned
  41 by acpi_get_name() and bail out in case of failure.
  42
  43 Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present")
  44 Link: https://bugzilla.kernel.org/show_bug.cgi?id=201381
  45 Reported-by: Ferry Toth <fntoth@gmail.com>
  46 Tested-by: Ferry Toth<fntoth@gmail.com>
  47 Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  48 Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
  49 Cc: 4.1+ <stable@vger.kernel.org> # 4.1+
  50 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  51 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  52
  53 ---
  54  drivers/acpi/device_sysfs.c |    6 +++++-
  55  1 file changed, 5 insertions(+), 1 deletion(-)
  56
  57 --- a/drivers/acpi/device_sysfs.c
  58 +++ b/drivers/acpi/device_sysfs.c
  59 @@ -202,11 +202,15 @@ static int create_of_modalias(struct acp
  60  {
  61         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
  62         const union acpi_object *of_compatible, *obj;
  63 +       acpi_status status;
  64         int len, count;
  65         int i, nval;
  66         char *c;
  67
  68 -       acpi_get_name(acpi_dev->handle, ACPI_SINGLE_NAME, &buf);
  69 +       status = acpi_get_name(acpi_dev->handle, ACPI_SINGLE_NAME, &buf);
  70 +       if (ACPI_FAILURE(status))
  71 +               return -ENODEV;
  72 +
  73         /* DT strings are all in lower case */
  74         for (c = buf.pointer; *c != '\0'; c++)
  75                 *c = tolower(*c);