[PATCH 12/12] kernel/trace: Add missing unlock

[PATCH 12/12] kernel/trace: Add missing unlock

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

In some error handling cases the lock is not unlocked.  The return is
converted to a goto, to share the unlock at the end of the function.

A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
expression E1;
identifier f;
@@

f (...) { <+...
* spin_lock_irq (E1,...);
... when != E1
* return ...;
...+> }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 kernel/trace/ring_buffer.c          |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 05a9f83..cd2e1d8 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1201,18 +1201,19 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 
 	for (i = 0; i < nr_pages; i++) {
 		if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
-			return;
+			goto out;
 		p = cpu_buffer->pages->next;
 		bpage = list_entry(p, struct buffer_page, list);
 		list_del_init(&bpage->list);
 		free_buffer_page(bpage);
 	}
 	if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
-		return;
+		goto out;
 
 	rb_reset_cpu(cpu_buffer);
 	rb_check_pages(cpu_buffer);
 
+out:
 	spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
@@ -1229,7 +1230,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 
 	for (i = 0; i < nr_pages; i++) {
 		if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
-			return;
+			goto out;
 		p = pages->next;
 		bpage = list_entry(p, struct buffer_page, list);
 		list_del_init(&bpage->list);
@@ -1238,6 +1239,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 	rb_reset_cpu(cpu_buffer);
 	rb_check_pages(cpu_buffer);
 
+out:
 	spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 

Re: [PATCH 12/12] kernel/trace: Add missing unlock

[Steven Rostedt]

On Mon, 2010-03-29 at 17:37 +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> In some error handling cases the lock is not unlocked.  The return is
> converted to a goto, to share the unlock at the end of the function.
> 
> A simplified version of the semantic patch that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @r exists@
> expression E1;
> identifier f;
> @@
> 
> f (...) { <+...
> * spin_lock_irq (E1,...);
> ... when != E1
> * return ...;
> ...+> }
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>

Applied, thanks!

-- Steve

> ---
>  kernel/trace/ring_buffer.c          |    8 +++++---
>  1 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
> index 05a9f83..cd2e1d8 100644
> --- a/kernel/trace/ring_buffer.c
> +++ b/kernel/trace/ring_buffer.c
> @@ -1201,18 +1201,19 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
>  
>  	for (i = 0; i < nr_pages; i++) {
>  		if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
> -			return;
> +			goto out;
>  		p = cpu_buffer->pages->next;
>  		bpage = list_entry(p, struct buffer_page, list);
>  		list_del_init(&bpage->list);
>  		free_buffer_page(bpage);
>  	}
>  	if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
> -		return;
> +		goto out;
>  
>  	rb_reset_cpu(cpu_buffer);
>  	rb_check_pages(cpu_buffer);
>  
> +out:
>  	spin_unlock_irq(&cpu_buffer->reader_lock);
>  }
>  
> @@ -1229,7 +1230,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
>  
>  	for (i = 0; i < nr_pages; i++) {
>  		if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
> -			return;
> +			goto out;
>  		p = pages->next;
>  		bpage = list_entry(p, struct buffer_page, list);
>  		list_del_init(&bpage->list);
> @@ -1238,6 +1239,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
>  	rb_reset_cpu(cpu_buffer);
>  	rb_check_pages(cpu_buffer);
>  
> +out:
>  	spin_unlock_irq(&cpu_buffer->reader_lock);
>  }
>  

[tip:tracing/urgent] ring-buffer: Add missing unlock

[tip-bot for Julia Lawall]

Commit-ID:  292f60c0c4ab44aa2d589ba03c12e64a3b3c5e38
Gitweb:     http://git.kernel.org/tip/292f60c0c4ab44aa2d589ba03c12e64a3b3c5e38
Author:     Julia Lawall <julia@diku.dk>
AuthorDate: Mon, 29 Mar 2010 17:37:02 +0200
Committer:  Steven Rostedt <rostedt@goodmis.org>
CommitDate: Mon, 29 Mar 2010 15:23:24 -0400

ring-buffer: Add missing unlock

In some error handling cases the lock is not unlocked.  The return is
converted to a goto, to share the unlock at the end of the function.

A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
expression E1;
identifier f;
@@

f (...) { <+...
* spin_lock_irq (E1,...);
... when != E1
* return ...;
...+> }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
LKML-Reference: <Pine.LNX.4.64.1003291736440.21896@ask.diku.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index d1187ef..9a0f9bf 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1209,18 +1209,19 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 
 	for (i = 0; i < nr_pages; i++) {
 		if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
-			return;
+			goto out;
 		p = cpu_buffer->pages->next;
 		bpage = list_entry(p, struct buffer_page, list);
 		list_del_init(&bpage->list);
 		free_buffer_page(bpage);
 	}
 	if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
-		return;
+		goto out;
 
 	rb_reset_cpu(cpu_buffer);
 	rb_check_pages(cpu_buffer);
 
+out:
 	spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
@@ -1237,7 +1238,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 
 	for (i = 0; i < nr_pages; i++) {
 		if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
-			return;
+			goto out;
 		p = pages->next;
 		bpage = list_entry(p, struct buffer_page, list);
 		list_del_init(&bpage->list);
@@ -1246,6 +1247,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 	rb_reset_cpu(cpu_buffer);
 	rb_check_pages(cpu_buffer);
 
+out:
 	spin_unlock_irq(&cpu_buffer->reader_lock);
 }