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fs/pstore: provide panic data even in suspend

PATCH In review [email protected] 2 participants 2 messages Aug 5, 2015

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#0 lore raw

PATCH 1/1 fs/pstore: provide panic data even in suspend

From: yangdongdong <[email protected]>

This also enables panic and oops messages which in suspend context to be logged into ramoops console buffer where it can be read back at some later point.

Signed-off-by yangdongdong <[email protected]>
Signed-off-by gulinghua <[email protected]>
---
 fs/pstore/ram.c            | 21 +++++++++++++++++++++
 include/linux/pstore_ram.h |  1 +
 kernel/printk/printk.c     |  6 ++++++
 3 files changed, 28 insertions(+)
fs/pstore/ram.c +21 -0
index 6c26c4d..f84c5ab 100644
@@ -642,8 +642,28 @@ static void ramoops_register_dummy(void)
 	}
 }
 
+static int ramoops_console_notify(struct notifier_block *this,
+		unsigned long event, void *ptr)
+{
+	pr_emerg("ramoops unlock console ...\n");
+	emergency_unlock_console();
+
+	return 0;
+}
+
+static struct notifier_block ramoop_nb = {
+	.notifier_call = ramoops_console_notify,
+	.priority = INT_MAX,
+};
+
+static void ramoops_prepare(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb);
+}
+
 static int __init ramoops_init(void)
 {
+	ramoops_prepare();
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }

@@ -654,6 +674,7 @@ static void __exit ramoops_exit(void)
 	platform_driver_unregister(&ramoops_driver);
 	platform_device_unregister(dummy);
 	kfree(dummy_data);
+	atomic_notifier_chain_unregister(&panic_notifier_list, &ramoop_nb);
 }
 module_exit(ramoops_exit);
include/linux/pstore_ram.h +1 -0
index 9c9d6c1..826a35b 100644
@@ -52,6 +52,7 @@ struct persistent_ram_zone {
 	size_t old_log_size;
 };
 
+extern void emergency_unlock_console(void);
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
 			unsigned int memtype);
kernel/printk/printk.c +6 -0
index cf8c242..ece645c 100644
@@ -2107,6 +2107,12 @@ void resume_console(void)
 	console_unlock();
 }
 
+void emergency_unlock_console(void)
+{
+	resume_console();
+}
+EXPORT_SYMBOL(emergency_unlock_console);
+
 /**
  * console_cpu_notify - print deferred console messages after CPU hotplug
  * @self: notifier struct
Signature · 1 line
2.5.0
#1 lore raw
Quoted 8 lines · On 08/05/2015 08:11 AM, [email protected] wrote:

From: yangdongdong <[email protected]>

This also enables panic and oops messages which in suspend context to be logged into ramoops console buffer where it can be read back at some later point.

Signed-off-by yangdongdong <[email protected]>
Signed-off-by gulinghua <[email protected]>

I have a small comment on the code below.

-Alex

Quoted 40 lines
---
 fs/pstore/ram.c            | 21 +++++++++++++++++++++
 include/linux/pstore_ram.h |  1 +
 kernel/printk/printk.c     |  6 ++++++
 3 files changed, 28 insertions(+)
fs/pstore/ram.c +20 -0
index 6c26c4d..f84c5ab 100644
@@ -642,8 +642,28 @@ static void ramoops_register_dummy(void)
 	}
 }
 
+static int ramoops_console_notify(struct notifier_block *this,
+		unsigned long event, void *ptr)
+{
+	pr_emerg("ramoops unlock console ...\n");
+	emergency_unlock_console();
+
+	return 0;
+}
+
+static struct notifier_block ramoop_nb = {
+	.notifier_call = ramoops_console_notify,
+	.priority = INT_MAX,
+};
+
+static void ramoops_prepare(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb);
+}
+
 static int __init ramoops_init(void)
 {
+	ramoops_prepare();
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }

fs/pstore/ram.c static void __exit ramoops_exit(void) · line 677

Quoted 4 lines
fs/pstore/ram.c +1 -0
@@ -654,6 +674,7 @@ static void __exit ramoops_exit(void)
 	platform_driver_unregister(&ramoops_driver);
 	platform_device_unregister(dummy);
 	kfree(dummy_data);
+	atomic_notifier_chain_unregister(&panic_notifier_list, &ramoop_nb);

I would say either wrap this atomic_notificer_chain_unregister() call in a trivial function ramoops_unprepare(), or (preferably) get rid of ramoops_prepare().

Quoted 33 lines
fs/pstore/ram.c +0 -0
 }
 module_exit(ramoops_exit);
include/linux/pstore_ram.h +1 -0
index 9c9d6c1..826a35b 100644
@@ -52,6 +52,7 @@ struct persistent_ram_zone {
 	size_t old_log_size;
 };
 
+extern void emergency_unlock_console(void);
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
 			unsigned int memtype);
kernel/printk/printk.c +6 -0
index cf8c242..ece645c 100644
@@ -2107,6 +2107,12 @@ void resume_console(void)
 	console_unlock();
 }
 
+void emergency_unlock_console(void)
+{
+	resume_console();
+}
+EXPORT_SYMBOL(emergency_unlock_console);
+
 /**
  * console_cpu_notify - print deferred console messages after CPU hotplug
  * @self: notifier struct