Re: BUG: key ffff880c1148c478 not in .data! (V3.10.0)

From: Mauro Carvalho Chehab
Date: Fri Jul 12 2013 - 09:58:12 EST


Em 12-07-2013 10:41, Borislav Petkov escreveu:
On Fri, Jul 12, 2013 at 10:04:28AM +0200, Markus Trippelsdorf wrote:
Mauro said he will fix this in the coming weeks:

http://article.gmane.org/gmane.linux.kernel/1522719
Here's a possible fix which works fine here. Markus, if you could verify
please...

I probably should also tag it for stable since the issue is in 3.10.
I'll leave it in -next a bit though, to have some coverage.

--
From: Borislav Petkov <bp@xxxxxxx>
Date: Fri, 12 Jul 2013 10:53:38 +0200
Subject: [PATCH] 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 it is handed in to lockdep. However, struct mem_ctl_info embeds
struct bus_type (the whole struct, not a pointer to it) which gets
dynamically allocated.

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

Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>
Cc: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
drivers/edac/edac_mc.c | 6 ++++++
drivers/edac/edac_mc_sysfs.c | 28 +++++++++++++++-------------
drivers/edac/i5100_edac.c | 2 +-
include/linux/edac.h | 2 +-
4 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 27e86d938262..2179f48cfe16 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -48,6 +48,10 @@ static LIST_HEAD(mc_devices);
*/
static void const *edac_mc_owner;
+static struct bus_type mc_bus = {
+ .dev_name = "edac_mc",
+};
+
unsigned edac_dimm_info_location(struct dimm_info *dimm, char *buf,
unsigned len)
{
@@ -762,6 +766,8 @@ 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;
+
if (edac_create_sysfs_mci_device(mci)) {
edac_mc_printk(mci, KERN_WARNING,
"failed to create sysfs device\n");
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c
index 67610a6ebf87..c4d700a577d2 100644
--- a/drivers/edac/edac_mc_sysfs.c
+++ b/drivers/edac/edac_mc_sysfs.c
@@ -370,7 +370,7 @@ static int edac_create_csrow_object(struct mem_ctl_info *mci,
return -ENODEV;
csrow->dev.type = &csrow_attr_type;
- csrow->dev.bus = &mci->bus;
+ csrow->dev.bus = mci->bus;
device_initialize(&csrow->dev);
csrow->dev.parent = &mci->dev;
csrow->mci = mci;
@@ -605,7 +605,7 @@ static int edac_create_dimm_object(struct mem_ctl_info *mci,
dimm->mci = mci;
dimm->dev.type = &dimm_attr_type;
- dimm->dev.bus = &mci->bus;
+ dimm->dev.bus = mci->bus;
device_initialize(&dimm->dev);
dimm->dev.parent = &mci->dev;
@@ -975,11 +975,13 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
* The memory controller needs its own bus, in order to avoid
* namespace conflicts at /sys/bus/edac.
*/
- mci->bus.name = kasprintf(GFP_KERNEL, "mc%d", mci->mc_idx);
- if (!mci->bus.name)
+ mci->bus->name = kasprintf(GFP_KERNEL, "mc%d", mci->mc_idx);
+ if (!mci->bus->name)
return -ENOMEM;

This will be overriding the content of the static var mc_bus every for every
new memory controller. Are you sure that bus.name is only used on register,
or if its contents is stored somewhere?

Otherwise, you may have troubles at module removal and/or on other places.

Regards,
Mauro
- edac_dbg(0, "creating bus %s\n", mci->bus.name);
- err = bus_register(&mci->bus);
+
+ edac_dbg(0, "creating bus %s\n", mci->bus->name);
+
+ err = bus_register(mci->bus);
if (err < 0)
return err;
@@ -988,7 +990,7 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
device_initialize(&mci->dev);
mci->dev.parent = mci_pdev;
- mci->dev.bus = &mci->bus;
+ mci->dev.bus = mci->bus;
dev_set_name(&mci->dev, "mc%d", mci->mc_idx);
dev_set_drvdata(&mci->dev, mci);
pm_runtime_forbid(&mci->dev);
@@ -997,8 +999,8 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci)
err = device_add(&mci->dev);
if (err < 0) {
edac_dbg(1, "failure: create device %s\n", dev_name(&mci->dev));
- bus_unregister(&mci->bus);
- kfree(mci->bus.name);
+ bus_unregister(mci->bus);
+ kfree(mci->bus->name);
return err;
}
@@ -1064,8 +1066,8 @@ fail:
}
fail2:
device_unregister(&mci->dev);
- bus_unregister(&mci->bus);
- kfree(mci->bus.name);
+ bus_unregister(mci->bus);
+ kfree(mci->bus->name);
return err;
}
@@ -1098,8 +1100,8 @@ void edac_unregister_sysfs(struct mem_ctl_info *mci)
{
edac_dbg(1, "Unregistering device %s\n", dev_name(&mci->dev));
device_unregister(&mci->dev);
- bus_unregister(&mci->bus);
- kfree(mci->bus.name);
+ bus_unregister(mci->bus);
+ kfree(mci->bus->name);
}
static void mc_attr_release(struct device *dev)
diff --git a/drivers/edac/i5100_edac.c b/drivers/edac/i5100_edac.c
index 1b635178cc44..157b934e8ce3 100644
--- a/drivers/edac/i5100_edac.c
+++ b/drivers/edac/i5100_edac.c
@@ -974,7 +974,7 @@ static int i5100_setup_debugfs(struct mem_ctl_info *mci)
if (!i5100_debugfs)
return -ENODEV;
- priv->debugfs = debugfs_create_dir(mci->bus.name, i5100_debugfs);
+ priv->debugfs = debugfs_create_dir(mci->bus->name, i5100_debugfs);
if (!priv->debugfs)
return -ENOMEM;
diff --git a/include/linux/edac.h b/include/linux/edac.h
index 0b763276f619..a9cc845f9762 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -622,7 +622,7 @@ struct edac_raw_error_desc {
*/
struct mem_ctl_info {
struct device dev;
- struct bus_type bus;
+ struct bus_type *bus;
struct list_head link; /* for global list of mem_ctl_info structs */

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