EDAC: Fix lockdep splat

Fix the following:

BUG: key ffff88043bdd0330 not in .data!
------------[ cut here ]------------
WARNING: at kernel/lockdep.c:2987 lockdep_init_map+0x565/0x5a0()
DEBUG_LOCKS_WARN_ON(1)
Modules linked in: glue_helper sb_edac(+) edac_core snd acpi_cpufreq lrw gf128mul ablk_helper iTCO_wdt evdev i2c_i801 dcdbas button cryptd pcspkr iTCO_vendor_support usb_common lpc_ich mfd_core soundcore mperf processor microcode
CPU: 2 PID: 599 Comm: modprobe Not tainted 3.10.0 #1
Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013
 0000000000000009 ffff880439a1d920 ffffffff8160a9a9 ffff880439a1d958
 ffffffff8103d9e0 ffff88043af4a510 ffffffff81a16e11 0000000000000000
 ffff88043bdd0330 0000000000000000 ffff880439a1d9b8 ffffffff8103dacc
Call Trace:
  dump_stack
  warn_slowpath_common
  warn_slowpath_fmt
  lockdep_init_map
  ? trace_hardirqs_on_caller
  ? trace_hardirqs_on
  debug_mutex_init
  __mutex_init
  bus_register
  edac_create_sysfs_mci_device
  edac_mc_add_mc
  sbridge_probe
  pci_device_probe
  driver_probe_device
  __driver_attach
  ? driver_probe_device
  bus_for_each_dev
  driver_attach
  bus_add_driver
  driver_register
  __pci_register_driver
  ? 0xffffffffa0010fff
  sbridge_init
  ? 0xffffffffa0010fff
  do_one_initcall
  load_module
  ? unset_module_init_ro_nx
  SyS_init_module
  tracesys
---[ end trace d24a70b0d3ddf733 ]---
EDAC MC0: Giving out device to 'sbridge_edac.c' 'Sandy Bridge Socket#0': DEV 0000:3f:0e.0
EDAC sbridge: Driver loaded.

What happens is that bus_register needs a statically allocated lock_key
because the last is handed in to lockdep. However, struct mem_ctl_info
embeds struct bus_type (the whole struct, not a pointer to it) and the
whole thing gets dynamically allocated.

Fix this by using a statically allocated struct bus_type for the MC bus.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: stable@kernel.org # v3.10
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 27e86d938262..89e109022d78 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -48,6 +48,8 @@ static LIST_HEAD(mc_devices);
  */
 static void const *edac_mc_owner;
 
+static struct bus_type mc_bus[EDAC_MAX_MCS];
+
 unsigned edac_dimm_info_location(struct dimm_info *dimm, char *buf,
                                  unsigned len)
 {
@@ -723,6 +725,11 @@ int edac_mc_add_mc(struct mem_ctl_info *mci)
         int ret = -EINVAL;
         edac_dbg(0, "\n");
 
+        if (mci->mc_idx >= EDAC_MAX_MCS) {
+                pr_warn_once("Too many memory controllers: %d\n", mci->mc_idx);
+                return -ENODEV;
+        }
+
 #ifdef CONFIG_EDAC_DEBUG
         if (edac_debug_level >= 3)
                 edac_mc_dump_mci(mci);
@@ -762,6 +769,8 @@ int edac_mc_add_mc(struct mem_ctl_info *mci)
         /* set load time so that error rate can be tracked */
         mci->start_time = jiffies;
 
+        mci->bus = &mc_bus[mci->mc_idx];
+
         if (edac_create_sysfs_mci_device(mci)) {
                 edac_mc_printk(mci, KERN_WARNING,
                         "failed to create sysfs device\n");