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fs/pstore: provide panic data even in suspend

PATCH Superseded [email protected] 1 participant 1 message Aug 5, 2015

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Printk Pstore filesystem

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

From: yangdongdong <[email protected]>

Update subject from ramoops to fs/pstore and convert all characters into English.

Good comments. It is valuable for code readable. Here is not necessary wrap atomic_notifier_chain_register into ramoops_prepare. The updated patch as below:

Quoted 1 line

From 5ec3976e2b55dfaf8bd1bc88c5a9c05762148fef Mon Sep 17 00:00:00 2001

From: yangdongdong <[email protected]>
Date: Wed, 5 Aug 2015 18:51:17 +0800
Subject: [PATCH] ramoops: provide panic data even in suspend

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            | 16 ++++++++++++++++
 include/linux/pstore_ram.h |  1 +
 kernel/printk/printk.c     |  6 ++++++
 3 files changed, 23 insertions(+)
fs/pstore/ram.c +16 -0
index 6c26c4d..3d981a1 100644
@@ -642,8 +642,23 @@ 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 int __init ramoops_init(void)
 {
+	atomic_notifier_chain_register(&panic_notifier_list, &ramoop_nb);
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }

@@ -654,6 +669,7 @@ 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 · 11 lines
2.5.0

Thanks,
Andy

-----original email-----
Send: Alex Elder [mailto:[email protected]]
Send time: Wed, 5 Aug 2015 21:23
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Cc: [email protected]
Subject: Re: [PATCH] fs/pstore: provide panic data even in suspend
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 39 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 index 6c26c4d..f84c5ab renamed from fs/pstore/ram.c +0 -0

100644

fs/pstore/ram.c +19 -0
@@ -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 index renamed from kernel/printk/printk.c +0 -0

cf8c242..ece645c 100644

kernel/printk/printk.c +6 -0
@@ -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