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edac: avoid mce decoding crash after edac driver unloaded
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commit e35fca4 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 [aosp-mirror#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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@poondog
Chen Gong authored and poondog committed Nov 19, 2014
1 parent f1cda8a commit afc9d9e
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Showing 2 changed files with 8 additions and 15 deletions.
15 changes: 4 additions & 11 deletions drivers/edac/i7core_edac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1932,12 +1932,6 @@ static int i7core_mce_check_error(struct notifier_block *nb, unsigned long val,
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();
Expand Down Expand Up @@ -2234,8 +2228,6 @@ static void i7core_unregister_mci(struct i7core_dev *i7core_dev)
if (pvt->enable_scrub)
disable_sdram_scrub_setting(mci);

mce_unregister_decode_chain(&i7_mce_dec);

/* Disable EDAC polling */
i7core_pci_ctl_release(pvt);

Expand Down Expand Up @@ -2336,8 +2328,6 @@ static int i7core_register_mci(struct i7core_dev *i7core_dev)
/* DCLK for scrub rate setting */
pvt->dclk_freq = get_dclk_freq();

mce_register_decode_chain(&i7_mce_dec);

return 0;

fail0:
Expand Down Expand Up @@ -2481,8 +2471,10 @@ static int __init i7core_init(void)

pci_rc = pci_register_driver(&i7core_driver);

if (pci_rc >= 0)
if (pci_rc >= 0) {
mce_register_decode_chain(&i7_mce_dec);
return 0;
}

i7core_printk(KERN_ERR, "Failed to register device with error %d.\n",
pci_rc);
Expand All @@ -2498,6 +2490,7 @@ static void __exit i7core_exit(void)
{
debugf2("MC: " __FILE__ ": %s()\n", __func__);
pci_unregister_driver(&i7core_driver);
mce_unregister_decode_chain(&i7_mce_dec);
}

module_init(i7core_init);
Expand Down
8 changes: 4 additions & 4 deletions drivers/edac/sb_edac.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1669,8 +1669,6 @@ static void sbridge_unregister_mci(struct sbridge_dev *sbridge_dev)
debugf0("MC: " __FILE__ ": %s(): mci = %p, dev = %p\n",
__func__, mci, &sbridge_dev->pdev[0]->dev);

mce_unregister_decode_chain(&sbridge_mce_dec);

/* Remove MC sysfs nodes */
edac_mc_del_mc(mci->dev);

Expand Down Expand Up @@ -1738,7 +1736,6 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev)
goto fail0;
}

mce_register_decode_chain(&sbridge_mce_dec);
return 0;

fail0:
Expand Down Expand Up @@ -1867,8 +1864,10 @@ static int __init sbridge_init(void)

pci_rc = pci_register_driver(&sbridge_driver);

if (pci_rc >= 0)
if (pci_rc >= 0) {
mce_register_decode_chain(&sbridge_mce_dec);
return 0;
}

sbridge_printk(KERN_ERR, "Failed to register device with error %d.\n",
pci_rc);
Expand All @@ -1884,6 +1883,7 @@ static void __exit sbridge_exit(void)
{
debugf2("MC: " __FILE__ ": %s()\n", __func__);
pci_unregister_driver(&sbridge_driver);
mce_unregister_decode_chain(&sbridge_mce_dec);
}

module_init(sbridge_init);
Expand Down

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