[PATCH] Fix memleak bug 13362

Jeremy Allison jra at samba.org
Mon May 14 23:05:52 UTC 2018


On Mon, May 14, 2018 at 08:45:58PM +0200, Volker Lendecke via samba-technical wrote:
> Hi!
> 
> Reporter confirmed it fixes the issue. Thanks to Szombathelyi György
> <gyurco at freemail.hu> for the logs and tests.
> 
> Review appreciated!

Been following this one in the bug report.

Nice simple fix.

LGTM, RB+ and pushed !

Jeremy

> -- 
> SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
> phone: +49-551-370000-0, fax: +49-551-370000-9
> AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
> http://www.sernet.de, mailto:kontakt at sernet.de

> From 2818b6a221776d4d1ab0ee5e880260c22781e1ac Mon Sep 17 00:00:00 2001
> From: Volker Lendecke <vl at samba.org>
> Date: Mon, 7 May 2018 16:41:55 +0200
> Subject: [PATCH 1/2] lib: Put "results_store" into a doubly linked list
> 
> Bug: https://bugzilla.samba.org/show_bug.cgi?id=13362
> Signed-off-by: Volker Lendecke <vl at samba.org>
> ---
>  lib/ldb/modules/paged_results.c | 25 +++++--------------------
>  1 file changed, 5 insertions(+), 20 deletions(-)
> 
> diff --git a/lib/ldb/modules/paged_results.c b/lib/ldb/modules/paged_results.c
> index de014a39699..aafbcbf4483 100644
> --- a/lib/ldb/modules/paged_results.c
> +++ b/lib/ldb/modules/paged_results.c
> @@ -35,6 +35,7 @@
>  #include "replace.h"
>  #include "system/filesys.h"
>  #include "system/time.h"
> +#include "dlinklist.h"
>  #include "ldb_module.h"
>  
>  struct message_store {
> @@ -48,14 +49,13 @@ struct message_store {
>  struct private_data;
>  
>  struct results_store {
> +	struct results_store *prev, *next;
>  
>  	struct private_data *priv;
>  
>  	char *cookie;
>  	time_t timestamp;
>  
> -	struct results_store *next;
> -
>  	struct message_store *first;
>  	struct message_store *last;
>  	int num_entries;
> @@ -75,22 +75,8 @@ struct private_data {
>  static int store_destructor(struct results_store *del)
>  {
>  	struct private_data *priv = del->priv;
> -	struct results_store *loop;
> -
> -	if (priv->store == del) {
> -		priv->store = del->next;
> -		return 0;
> -	}
> -
> -	for (loop = priv->store; loop; loop = loop->next) {
> -		if (loop->next == del) {
> -			loop->next = del->next;
> -			return 0;
> -		}
> -	}
> -
> -	/* is not in list ? */
> -	return -1;
> +	DLIST_REMOVE(priv->store, del);
> +	return 0;
>  }
>  
>  static struct results_store *new_store(struct private_data *priv)
> @@ -120,8 +106,7 @@ static struct results_store *new_store(struct private_data *priv)
>  	newr->first_ref = NULL;
>  	newr->controls = NULL;
>  
> -	newr->next = priv->store;
> -	priv->store = newr;
> +	DLIST_ADD(priv->store, newr);
>  
>  	talloc_set_destructor(newr, store_destructor);
>  
> -- 
> 2.11.0
> 
> 
> From 90ebf48be88806ec48c90b860519138a9932617c Mon Sep 17 00:00:00 2001
> From: Volker Lendecke <vl at samba.org>
> Date: Mon, 7 May 2018 16:53:00 +0200
> Subject: [PATCH 2/2] lib: Hold at most 10 outstanding paged result cookies
> 
> Bug: https://bugzilla.samba.org/show_bug.cgi?id=13362
> Signed-off-by: Volker Lendecke <vl at samba.org>
> ---
>  lib/ldb/modules/paged_results.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/lib/ldb/modules/paged_results.c b/lib/ldb/modules/paged_results.c
> index aafbcbf4483..ecb22271d28 100644
> --- a/lib/ldb/modules/paged_results.c
> +++ b/lib/ldb/modules/paged_results.c
> @@ -36,6 +36,7 @@
>  #include "system/filesys.h"
>  #include "system/time.h"
>  #include "dlinklist.h"
> +#include <assert.h>
>  #include "ldb_module.h"
>  
>  struct message_store {
> @@ -68,6 +69,7 @@ struct results_store {
>  
>  struct private_data {
>  	uint32_t next_free_id;
> +	size_t num_stores;
>  	struct results_store *store;
>  	
>  };
> @@ -76,6 +78,10 @@ static int store_destructor(struct results_store *del)
>  {
>  	struct private_data *priv = del->priv;
>  	DLIST_REMOVE(priv->store, del);
> +
> +	assert(priv->num_stores > 0);
> +	priv->num_stores -= 1;
> +
>  	return 0;
>  }
>  
> @@ -108,8 +114,21 @@ static struct results_store *new_store(struct private_data *priv)
>  
>  	DLIST_ADD(priv->store, newr);
>  
> +	assert(priv->num_stores < SIZE_MAX);
> +	priv->num_stores += 1;
> +
>  	talloc_set_destructor(newr, store_destructor);
>  
> +	if (priv->num_stores > 10) {
> +		struct results_store *last;
> +		/*
> +		 * 10 is the default for MaxResultSetsPerConn --
> +		 * possibly need to parameterize it.
> +		 */
> +		last = DLIST_TAIL(priv->store);
> +		TALLOC_FREE(last);
> +	}
> +
>  	return newr;
>  }
>  
> @@ -366,6 +385,8 @@ static int paged_search(struct ldb_module *module, struct ldb_request *req)
>  			return LDB_ERR_UNWILLING_TO_PERFORM;
>  		}
>  
> +		DLIST_PROMOTE(private_data->store, current);
> +
>  		ac->store = current;
>  
>  		/* check if it is an abandon */
> @@ -397,6 +418,7 @@ static int paged_request_init(struct ldb_module *module)
>  	}
>  
>  	data->next_free_id = 1;
> +	data->num_stores = 0;
>  	data->store = NULL;
>  	ldb_module_set_private(module, data);
>  
> -- 
> 2.11.0
> 




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