elevator: fix double release for elevator module

PATCH In review Chao Yu 3 participants 4 messages Apr 23, 2015 – Apr 24, 2015 Block layer

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Chao Yu

author

2015-04-23 09:23 UTC #0 lore raw

PATCH 1/1 elevator: fix double release for elevator module

Our issue is descripted in below call path:
->elevator_init
->elevator_init_fn
->{cfq,deadline,noop}_init_queue
->elevator_alloc

    ->kzalloc_node

fail to call kzalloc_node and then put module in elevator_alloc;
fail to call elevator_init_fn and then put module again in elevator_init.

Remove elevator_put invoking in error path of elevator_alloc to avoid double release issue.

Signed-off-by Chao Yu <[email protected]>

---
 block/elevator.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

block/elevator.c +1 -4

index d146a5e..8985038 100644
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 
 	eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
 	if (unlikely(!eq))
-		goto err;
+		return NULL;
 
 	eq->type = e;
 	kobject_init(&eq->kobj, &elv_ktype);

@@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 	hash_init(eq->hash);
 
 	return eq;
-err:
-	elevator_put(e);
-	return NULL;
 }
 EXPORT_SYMBOL(elevator_alloc);

Signature · 1 line

2.3.3

Jeff Moyer

Reviewed-by on v1 1/1

2015-04-23 14:59 UTC #1 lore raw

Quoted 31 lines · Chao Yu

Our issue is descripted in below call path:
->elevator_init
->elevator_init_fn
->{cfq,deadline,noop}_init_queue
->elevator_alloc
    ->kzalloc_node
fail to call kzalloc_node and then put module in elevator_alloc;
fail to call elevator_init_fn and then put module again in elevator_init.
Remove elevator_put invoking in error path of elevator_alloc to avoid double release issue.
Signed-off-by Chao Yu <[email protected]>
---
 block/elevator.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
block/elevator.c +1 -1
index d146a5e..8985038 100644
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 
 	eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
 	if (unlikely(!eq))
-		goto err;
+		return NULL;
 
 	eq->type = e;
 	kobject_init(&eq->kobj, &elv_ktype);

block/elevator.c struct elevator_queue *elevator_alloc(struct request_queue *q, · line 169

Quoted 8 lines

block/elevator.c +0 -3

@@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 	hash_init(eq->hash);
 
 	return eq;
-err:
-	elevator_put(e);
-	return NULL;
 }
 EXPORT_SYMBOL(elevator_alloc);

You could have posted the two patches together, as they are related. Anyway, looks good to me.

Reviewed-by Jeff Moyer <[email protected]>

Jens Axboe

maintainer

2015-04-23 16:49 UTC #2 lore raw

Quoted 45 lines · Jeff Moyer

Quoted 31 lines · Chao Yu
Our issue is descripted in below call path:
->elevator_init
->elevator_init_fn
->{cfq,deadline,noop}_init_queue
    ->elevator_alloc
     ->kzalloc_node
    fail to call kzalloc_node and then put module in elevator_alloc;
fail to call elevator_init_fn and then put module again in elevator_init.
Remove elevator_put invoking in error path of elevator_alloc to avoid double release issue.
Signed-off-by Chao Yu <[email protected]>
---
  block/elevator.c | 5 +----
  1 file changed, 1 insertion(+), 4 deletions(-)
block/elevator.c +1 -1
index d146a5e..8985038 100644
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 
  	eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
  	if (unlikely(!eq))
-		goto err;
+		return NULL;
 
  	eq->type = e;
  	kobject_init(&eq->kobj, &elv_ktype);
block/elevator.c struct elevator_queue *elevator_alloc(struct request_queue *q, · line 169
Quoted 8 lines
block/elevator.c +0 -3
@@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
  	hash_init(eq->hash);
 
  	return eq;
-err:
-	elevator_put(e);
-	return NULL;
  }
  EXPORT_SYMBOL(elevator_alloc);
You could have posted the two patches together, as they are related. Anyway, looks good to me.

Quoted 1 line

Reviewed-by Jeff Moyer <[email protected]>

Agree, it should be one patch. I've combined them, and applied the fix for 4.1. Thanks.

Signature · 1 line

Jens Axboe

Chao Yu

author

2015-04-24 01:29 UTC #3 lore raw

Hi Jens and Jeff,

Thanks for your review and help! :)

Regards,

Quoted 60 lines

-----Original Message-----
From: Jens Axboe [mailto:[email protected]]
Sent: Friday, April 24, 2015 12:49 AM
To: Jeff Moyer; Chao Yu
Cc: [email protected]
Subject: Re: [PATCH] elevator: fix double release for elevator module
Quoted 45 lines · Jeff Moyer
Quoted 31 lines · Chao Yu
Our issue is descripted in below call path:
->elevator_init
->elevator_init_fn
->{cfq,deadline,noop}_init_queue
    ->elevator_alloc
     ->kzalloc_node
    fail to call kzalloc_node and then put module in elevator_alloc;
fail to call elevator_init_fn and then put module again in elevator_init.
Remove elevator_put invoking in error path of elevator_alloc to avoid double release issue.
Signed-off-by Chao Yu <[email protected]>
---
  block/elevator.c | 5 +----
  1 file changed, 1 insertion(+), 4 deletions(-)
block/elevator.c +1 -1
index d146a5e..8985038 100644
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 
  	eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
  	if (unlikely(!eq))
-		goto err;
+		return NULL;
 
  	eq->type = e;
  	kobject_init(&eq->kobj, &elv_ktype);
block/elevator.c struct elevator_queue *elevator_alloc(struct request_queue *q, · line 169
Quoted 8 lines
block/elevator.c +0 -3
@@ -165,9 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
  	hash_init(eq->hash);
 
  	return eq;
-err:
-	elevator_put(e);
-	return NULL;
  }
  EXPORT_SYMBOL(elevator_alloc);
You could have posted the two patches together, as they are related. Anyway, looks good to me.
Quoted 1 line
Reviewed-by Jeff Moyer <[email protected]>
Agree, it should be one patch. I've combined them, and applied the fix for 4.1. Thanks.
--
Jens Axboe