[ 03/48] edac: avoid mce decoding crash after edac driver unloaded

Ben Hutchings
2012-07-01T18:16:24Z

From: Chen Gong <gong.chen@linux.intel.com>

commit e35fca4791fcdd43dc1fd769797df40c562ab491 upstream.

Some edac drivers register themselves as mce decoders via
notifier_chain. But in current notifier_chain implementation logic,
it doesn't accept same notifier registered twice. If so, it will be
wrong when adding/removing the element from the list. For example,
on one SandyBridge platform, remove module sb_edac and then trigger
one error, it will hit oops because it has no mce decoder registered
but related notifier_chain still points to an invalid callback
function. Here is an example:

Call Trace:
[<ffffffff8150ef6a>] atomic_notifier_call_chain+0x1a/0x20
[<ffffffff8102b936>] mce_log+0x46/0x180
[<ffffffff8102eaea>] apei_mce_report_mem_error+0x4a/0x60
[<ffffffff812e19d2>] ghes_do_proc+0x192/0x210
[<ffffffff812e2066>] ghes_proc+0x46/0x70
[<ffffffff812e20d8>] ghes_notify_sci+0x48/0x80
[<ffffffff8150ef05>] notifier_call_chain+0x55/0x80
[<ffffffff81076f1a>] __blocking_notifier_call_chain+0x5a/0x80
[<ffffffff812aea11>] ? acpi_os_wait_events_complete+0x23/0x23
[<ffffffff81076f56>] blocking_notifier_call_chain+0x16/0x20
[<ffffffff812ddc4d>] acpi_hed_notify+0x19/0x1b
[<ffffffff812b16bd>] acpi_device_notify+0x19/0x1b
[<ffffffff812beb38>] acpi_ev_notify_dispatch+0x67/0x7f
[<ffffffff812aea3a>] acpi_os_execute_deferred+0x29/0x36
[<ffffffff81069dc2>] process_one_work+0x132/0x450
[<ffffffff8106bbcb>] worker_thread+0x17b/0x3c0
[<ffffffff8106ba50>] ? manage_workers+0x120/0x120
[<ffffffff81070aee>] kthread+0x9e/0xb0
[<ffffffff81514724>] kernel_thread_helper+0x4/0x10
[<ffffffff81070a50>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff81514720>] ? gs_change+0x13/0x13
Code: f3 49 89 d4 45 85 ed 4d 89 c6 48 8b 0f 74 48 48 85 c9 75 17 eb 41
0f 1f 80 00 00 00 00 41 83 ed 01 4c 89 f9 74 22 4d 85 ff 74 1d <4c> 8b
79 08 4c 89 e2 48 89 de 48 89 cf ff 11 4d 85 f6 74 04 41
RIP [<ffffffff8150eef6>] notifier_call_chain+0x46/0x80
RSP <ffff88042868fb20>
CR2: ffffffffa01af838
---[ end trace 0100930068e73e6f ]---
BUG: unable to handle kernel paging request at fffffffffffffff8
IP: [<ffffffff810705b0>] kthread_data+0x10/0x20
PGD 1a0d067 PUD 1a0e067 PMD 0
Oops: 0000 [#2] SMP

Only i7core_edac and sb_edac have such issues because they have more
than one memory controller which means they have to register mce
decoder many times.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
[bwh: Backported to 3.2: drivers call atomic_notifier_chain_{,un}register()
directly]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -1932,12 +1932,6 @@
if (mce->bank != 8)
return NOTIFY_DONE;

-#ifdef CONFIG_SMP
- /* Only handle if it is the right mc controller */
- if (mce->socketid != pvt->i7core_dev->socket)
- return NOTIFY_DONE;
-#endif
-
smp_rmb();
if ((pvt->mce_out + 1) % MCE_LOG_LEN == pvt->mce_in) {
smp_wmb();
@@ -2234,8 +2228,6 @@
if (pvt->enable_scrub)
disable_sdram_scrub_setting(mci);

- atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &i7_mce_dec);
-
/* Disable EDAC polling */
i7core_pci_ctl_release(pvt);

@@ -2336,8 +2328,6 @@
/* DCLK for scrub rate setting */
pvt->dclk_freq = get_dclk_freq();

- atomic_notifier_chain_register(&x86_mce_decoder_chain, &i7_mce_dec);
-
return 0;

fail0:
@@ -2481,8 +2471,10 @@

pci_rc = pci_register_driver(&i7core_driver);

- if (pci_rc >= 0)
+ if (pci_rc >= 0) {
+ atomic_notifier_chain_register(&x86_mce_decoder_chain, &i7_mce_dec);
return 0;
+ }

i7core_printk(KERN_ERR, "Failed to register device with error %d.\n",
pci_rc);
@@ -2498,6 +2490,7 @@
{
debugf2("MC: " __FILE__ ": %s()\n", __func__);
pci_unregister_driver(&i7core_driver);
+ atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &i7_mce_dec);
}

module_init(i7core_init);
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -1661,9 +1661,6 @@
debugf0("MC: " __FILE__ ": %s(): mci = %p, dev = %p\n",
__func__, mci, &sbridge_dev->pdev[0]->dev);

- atomic_notifier_chain_unregister(&x86_mce_decoder_chain,
- &sbridge_mce_dec);
-
/* Remove MC sysfs nodes */
edac_mc_del_mc(mci->dev);

@@ -1731,8 +1728,6 @@
goto fail0;
}

- atomic_notifier_chain_register(&x86_mce_decoder_chain,
- &sbridge_mce_dec);
return 0;

fail0:
@@ -1861,8 +1856,10 @@

pci_rc = pci_register_driver(&sbridge_driver);

- if (pci_rc >= 0)
+ if (pci_rc >= 0) {
+ atomic_notifier_chain_register(&x86_mce_decoder_chain, &sbridge_mce_dec);
return 0;
+ }

sbridge_printk(KERN_ERR, "Failed to register device with error %d.\n",
pci_rc);
@@ -1878,6 +1875,7 @@
{
debugf2("MC: " __FILE__ ": %s()\n", __func__);
pci_unregister_driver(&sbridge_driver);
+ atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &sbridge_mce_dec);
}

module_init(sbridge_init);