[PATCH] UBI: fix memory leak when use fastmap

[PATCH] UBI: fix memory leak when use fastmap

[wang.bo116]

Hello,
        Sorry, there is still something wrong with the previous patch's 
format, try to submit it again. When use ubi fastmap, there is a memory 
leak which will make destroy_ai() fail to free the slab alloced in 
scan_fast(). The following patch fix this problem by use a temporary 
"ubi_attach_info" variable in scan_fast().


diff -uprN a/linux-3.9-rc6/drivers/mtd/ubi/attach.c 
b/linux-3.9-rc6/drivers/mtd/ubi/attach.c
--- a/linux-3.9-rc6/drivers/mtd/ubi/attach.c    2013-04-08 
03:49:54.000000000 +0000
+++ b/linux-3.9-rc6/drivers/mtd/ubi/attach.c    2013-04-16 
03:22:47.343750000 +0000
@@ -1212,6 +1212,30 @@ static void destroy_ai(struct ubi_attach
        kfree(ai);
 }
 
+static struct ubi_attach_info *alloc_ai(const char *slab_name)
+{
+       struct ubi_attach_info *ai;
+
+       ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
+       if (!ai)
+               return ai;
+
+       INIT_LIST_HEAD(&ai->corr);
+       INIT_LIST_HEAD(&ai->free);
+       INIT_LIST_HEAD(&ai->erase);
+       INIT_LIST_HEAD(&ai->alien);
+       ai->volumes = RB_ROOT;
+       ai->aeb_slab_cache = kmem_cache_create(slab_name,
+                                          sizeof(struct ubi_ainf_peb),
+                                              0, 0, NULL);
+       if (!ai->aeb_slab_cache) {
+               kfree(ai);
+               ai = NULL;
+       }
+
+       return ai;
+}
+
 /**
  * scan_all - scan entire MTD device.
  * @ubi: UBI device description object
@@ -1315,8 +1339,13 @@ static int scan_fast(struct ubi_device *
        int err, pnum, fm_anchor = -1;
        unsigned long long max_sqnum = 0;
 
+       struct ubi_attach_info *fm_temp_ai = NULL;
        err = -ENOMEM;
 
+       fm_temp_ai = alloc_ai("ubi_scan_fastmap_slab_cache");
+       if (!fm_temp_ai)
+               goto out;
+
        ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
        if (!ech)
                goto out;
@@ -1331,7 +1360,7 @@ static int scan_fast(struct ubi_device *
                cond_resched();
 
                dbg_gen("process PEB %d", pnum);
-               err = scan_peb(ubi, ai, pnum, &vol_id, &sqnum);
+               err = scan_peb(ubi, fm_temp_ai, pnum, &vol_id, &sqnum);
                if (err < 0)
                        goto out_vidh;
 
@@ -1343,6 +1372,7 @@ static int scan_fast(struct ubi_device *
 
        ubi_free_vid_hdr(ubi, vidh);
        kfree(ech);
+       destroy_ai(fm_temp_ai);
 
        if (fm_anchor < 0)
                return UBI_NO_FASTMAP;
@@ -1351,6 +1381,7 @@ static int scan_fast(struct ubi_device *
 
 out_vidh:
        ubi_free_vid_hdr(ubi, vidh);
+       destroy_ai(fm_temp_ai);
 out_ech:
        kfree(ech);
 out:
@@ -1359,29 +1390,6 @@ out:
 
 #endif
 
-static struct ubi_attach_info *alloc_ai(const char *slab_name)
-{
-       struct ubi_attach_info *ai;
-
-       ai = kzalloc(sizeof(struct ubi_attach_info), GFP_KERNEL);
-       if (!ai)
-               return ai;
-
-       INIT_LIST_HEAD(&ai->corr);
-       INIT_LIST_HEAD(&ai->free);
-       INIT_LIST_HEAD(&ai->erase);
-       INIT_LIST_HEAD(&ai->alien);
-       ai->volumes = RB_ROOT;
-       ai->aeb_slab_cache = kmem_cache_create(slab_name,
-                                          sizeof(struct ubi_ainf_peb),
-                                              0, 0, NULL);
-       if (!ai->aeb_slab_cache) {
-               kfree(ai);
-               ai = NULL;
-       }
-
-       return ai;
-}
 
 /**
  * ubi_attach - attach an MTD device.
@@ -1419,7 +1427,7 @@ int ubi_attach(struct ubi_device *ubi, i
                                        return -ENOMEM;
                        }
 
-                       err = scan_all(ubi, ai, UBI_FM_MAX_START);
+                       err = scan_all(ubi, ai, 0);
                }
        }
 #else
 
diff -uprN a/linux-3.9-rc6/drivers/mtd/ubi/fastmap.c 
b/linux-3.9-rc6/drivers/mtd/ubi/fastmap.c
--- a/linux-3.9-rc6/drivers/mtd/ubi/fastmap.c   2013-04-08 
03:49:54.000000000 +0000
+++ b/linux-3.9-rc6/drivers/mtd/ubi/fastmap.c   2013-04-16 
03:22:17.468750000 +0000
@@ -552,21 +552,8 @@ static int ubi_attach_fastmap(struct ubi
        INIT_LIST_HEAD(&used);
        INIT_LIST_HEAD(&free);
        INIT_LIST_HEAD(&eba_orphans);
-       INIT_LIST_HEAD(&ai->corr);
-       INIT_LIST_HEAD(&ai->free);
-       INIT_LIST_HEAD(&ai->erase);
-       INIT_LIST_HEAD(&ai->alien);
-       ai->volumes = RB_ROOT;
        ai->min_ec = UBI_MAX_ERASECOUNTER;
 
-       ai->aeb_slab_cache = kmem_cache_create("ubi_ainf_peb_slab",
-                                          sizeof(struct ubi_ainf_peb),
-                                              0, 0, NULL);
-       if (!ai->aeb_slab_cache) {
-               ret = -ENOMEM;
-               goto fail;
-       }
-
        fmsb = (struct ubi_fm_sb *)(fm_raw);
        ai->max_sqnum = fmsb->sqnum;
        fm_pos += sizeof(struct ubi_fm_sb);

Re: [PATCH] UBI: fix memory leak when use fastmap

[richard -rw- weinberger]

Hi!

On Tue, Apr 16, 2013 at 10:53 AM,  <wang.bo116@zte.com.cn> wrote:
> Hello,
>         Sorry, there is still something wrong with the previous patch's
> format, try to submit it again. When use ubi fastmap, there is a memory
> leak which will make destroy_ai() fail to free the slab alloced in
> scan_fast(). The following patch fix this problem by use a temporary
> "ubi_attach_info" variable in scan_fast().

Thanks a lot for your patch!

Did you test it well?
We need to make sure that it does the right thing for the following cases:
1. fastmap disabled, attaching a non-fastmap volume
1. fastmap disabled, attaching a fastmap volume
3. fastmap enabled, attaching a non-fastmap volume
4. fastmap enablled, attaching a fastmap volume

--
Thanks,
//richard

Placing ext3 journal on mtd device

[d.soumyajit]

Hi,

In Ext3 performance can be improved by placing journal on SSD. I am able
to place ext3 journal on an external device. Can you please help me
placing ext3 journal on mtd device.

Thanks in Advance!

Soumyajit

Re: Placing ext3 journal on mtd device

[richard -rw- weinberger]

On Mon, Apr 29, 2013 at 6:08 PM,  <d.soumyajit@iitg.ernet.in> wrote:
> Hi,
>
> In Ext3 performance can be improved by placing journal on SSD. I am able
> to place ext3 journal on an external device. Can you please help me
> placing ext3 journal on mtd device.

*very* bad idea.

--
Thanks,
//richard