Re: [PATCH] ubifs: fix memory leak from c->sup_node

[Sascha Hauer]

On Tue, Jan 14, 2020 at 01:43:11PM +0800, quanyang.wang@xxxxxxxxxxxxx wrote:
> From: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>
> 
> The c->sup_node is allocated in function ubifs_read_sb_node but
> is not freed. This will cause memory leak as below:
> 
> unreferenced object 0xbc9ce000 (size 4096):
>   comm "mount", pid 500, jiffies 4294952946 (age 315.820s)
>   hex dump (first 32 bytes):
>     31 18 10 06 06 7b f1 11 02 00 00 00 00 00 00 00  1....{..........
>     00 10 00 00 06 00 00 00 00 00 00 00 08 00 00 00  ................
>   backtrace:
>     [<d1c503cd>] ubifs_read_superblock+0x48/0xebc
>     [<a20e14bd>] ubifs_mount+0x974/0x1420
>     [<8589ecc3>] legacy_get_tree+0x2c/0x50
>     [<5f1fb889>] vfs_get_tree+0x28/0xfc
>     [<bbfc7939>] do_mount+0x4f8/0x748
>     [<4151f538>] ksys_mount+0x78/0xa0
>     [<d59910a9>] ret_fast_syscall+0x0/0x54
>     [<1cc40005>] 0x7ea02790
> 
> Free it in ubifs_umount and in the error path of mount_ubifs.
> 
> Fixes: fd6150051bec ("ubifs: Store read superblock node")
> Signed-off-by: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>

Looks good.

Reviewed-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>

Sascha

> ---
>  fs/ubifs/super.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index 7d4547e5202d..a4412c259bb3 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -1599,6 +1599,7 @@ static int mount_ubifs(struct ubifs_info *c)
>  	vfree(c->ileb_buf);
>  	vfree(c->sbuf);
>  	kfree(c->bottom_up_buf);
> +	kfree(c->sup_node);
>  	ubifs_debugging_exit(c);
>  	return err;
>  }
> @@ -1641,6 +1642,7 @@ static void ubifs_umount(struct ubifs_info *c)
>  	vfree(c->ileb_buf);
>  	vfree(c->sbuf);
>  	kfree(c->bottom_up_buf);
> +	kfree(c->sup_node);
>  	ubifs_debugging_exit(c);
>  }
>  
> -- 
> 2.17.1
> 
> 

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