linux-kernel - [PATCH v2 1/1] intel_telemetry_debugfs: fix oops found while load/unload module test

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Message-Id: <709e8015ccece63cdf0c2e0cd491fd5ca2984e8d.1496351574.git.priyalee.kushwaha@intel.com>
Date:   Thu,  1 Jun 2017 14:33:29 -0700
From:   priyalee.kushwaha@...el.com
To:     dvhart@...radead.org, souvik.k.chakravarty@...el.com,
        andy@...radead.org
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        Priyalee Kushwaha <priyalee.kushwaha@...el.com>
Subject: [PATCH v2 1/1] intel_telemetry_debugfs: fix oops found while load/unload module test

From: Priyalee Kushwaha <priyalee.kushwaha@...el.com>

This fix oops found while testing load/unload test of
intel_telemetry_debugfs module. Module_init uses register_pm_notifier
for PM callbacks, but unregister_pm_notifier was missing from
module_exit.

 [ 97.481860] BUG: unable to handle kernel paging request at ffffffffa006f010
 [ 97.489742] IP: blocking_notifier_chain_register+0x3a/0xa0
 [ 97.495898] PGD 2e0a067
 [ 97.495899] PUD 2e0b063
 [ 97.498737] PMD 179e29067
 [ 97.501573] PTE 0

 [ 97.508423] Oops: 0000 1 PREEMPT SMP
 [ 97.512724] Modules linked in: intel_telemetry_debugfs intel_rapl gpio_keys dwc3 udc_core intel_telemetry_pltdrv intel_punit_ipc intel_telemetry_core rtc_cmos efivars x86_pkg_temp_thermal iwlwifi snd_hda_codec_hdmi soc_button_array btusb cfg80211 btrtl mei_me hci_uart btbcm mei btintel i915 bluetooth intel_pmc_ipc snd_hda_intel spi_pxa2xx_platform snd_hda_codec dwc3_pci snd_hda_core tpm_tis tpm_tis_core tpm efivarfs
 [ 97.558453] CPU: 0 PID: 889 Comm: modprobe Not tainted 4.11.0-rc6-intel-dev-bkc #1
 [ 97.566950] Hardware name: Intel Corp. Joule DVT3/SDS, BIOS GTPP181A.X64.0143.B30.1701132137 01/13/2017
 [ 97.577518] task: ffff8801793a21c0 task.stack: ffff8801793f0000
 [ 97.584162] RIP: 0010:blocking_notifier_chain_register+0x3a/0xa0
 [ 97.590903] RSP: 0018:ffff8801793f3c58 EFLAGS: 00010286
 [ 97.596802] RAX: ffffffffa006f000 RBX: ffffffff81e3ea20 RCX: 0000000000000000
 [ 97.604812] RDX: ffff880179eaf210 RSI: ffffffffa0131000 RDI: ffffffff81e3ea20
 [ 97.612821] RBP: ffff8801793f3c68 R08: 0000000000000006 R09: 000000000000005c
 [ 97.620847] R10: 0000000000000000 R11: 0000000000000006 R12: ffffffffa0131000
 [ 97.628855] R13: 0000000000000000 R14: ffff880176e35f48 R15: ffff8801793f3ea8
 [ 97.636865] FS: 00007f7eeba07700(0000) GS:ffff88017fc00000(0000) knlGS:0000000000000000
 [ 97.645948] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [ 97.652423] CR2: ffffffffa006f010 CR3: 00000001775ef000 CR4: 00000000003406f0
 [ 97.660423] Call Trace:
 [ 97.663166] ? 0xffffffffa0031000
 [ 97.666885] register_pm_notifier+0x18/0x20
 [ 97.671581] telemetry_debugfs_init+0x92/0x1000

Signed-off-by: Priyalee Kushwaha <priyalee.kushwaha@...el.com>
---
 drivers/platform/x86/intel_telemetry_debugfs.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/intel_telemetry_debugfs.c b/drivers/platform/x86/intel_telemetry_debugfs.c
index ef29f18..30f70b5 100644
--- a/drivers/platform/x86/intel_telemetry_debugfs.c
+++ b/drivers/platform/x86/intel_telemetry_debugfs.c
@@ -966,8 +966,10 @@ static int __init telemetry_debugfs_init(void)
 #endif /* CONFIG_PM_SLEEP */
 
 	debugfs_conf->telemetry_dbg_dir = debugfs_create_dir("telemetry", NULL);
-	if (!debugfs_conf->telemetry_dbg_dir)
-		return -ENOMEM;
+	if (!debugfs_conf->telemetry_dbg_dir) {
+		err = -ENOMEM;
+		goto out_pm;
+	}
 
 	f = debugfs_create_file("pss_info", S_IFREG | S_IRUGO,
 				debugfs_conf->telemetry_dbg_dir, NULL,
@@ -1014,6 +1016,10 @@ static int __init telemetry_debugfs_init(void)
 out:
 	debugfs_remove_recursive(debugfs_conf->telemetry_dbg_dir);
 	debugfs_conf->telemetry_dbg_dir = NULL;
+out_pm:
+#ifdef CONFIG_PM_SLEEP
+	unregister_pm_notifier(&pm_notifier);
+#endif /* CONFIG_PM_SLEEP */
 
 	return err;
 }
@@ -1022,6 +1028,9 @@ static void __exit telemetry_debugfs_exit(void)
 {
 	debugfs_remove_recursive(debugfs_conf->telemetry_dbg_dir);
 	debugfs_conf->telemetry_dbg_dir = NULL;
+#ifdef CONFIG_PM_SLEEP
+	unregister_pm_notifier(&pm_notifier);
+#endif /* CONFIG_PM_SLEEP */
 }
 
 late_initcall(telemetry_debugfs_init);
-- 
2.10.0