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

[Julia Lawall]

From: Julia Lawall <ju...@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 <ju...@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);
}

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[Steven Rostedt]

On Mon, 2010-03-29 at 17:37 +0200, Julia Lawall wrote:
> From: Julia Lawall <ju...@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 <ju...@diku.dk>

Applied, thanks!

-- Steve

[tip-bot for Julia Lawall]

Commit-ID: 292f60c0c4ab44aa2d589ba03c12e64a3b3c5e38
Gitweb: http://git.kernel.org/tip/292f60c0c4ab44aa2d589ba03c12e64a3b3c5e38
Author: Julia Lawall <ju...@diku.dk>
AuthorDate: Mon, 29 Mar 2010 17:37:02 +0200
Committer: Steven Rostedt <ros...@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 <ju...@diku.dk>
LKML-Reference: <Pine.LNX.4.64.10...@ask.diku.dk>
Signed-off-by: Steven Rostedt <ros...@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,