2022-04-22 00:37:51

by Nikolay Borisov

Subject: Re: [PATCH] btrfs: Fix a memory leak in btrfs_ioctl_balance()

On 21.04.22 г. 12:51 ч., Haowen Bai wrote:
> Free "bargs" before return.
>
> Signed-off-by: Haowen Bai <[email protected]>
> ---
> fs/btrfs/ioctl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index f08233c2b0b2..d4c8bea914b7 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4389,13 +4389,13 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
> /* this is (2) */
> mutex_unlock(&fs_info->balance_mutex);
> ret = -EINPROGRESS;
> - goto out;
> + goto out_bargs;
> }
> } else {
> /* this is (1) */
> mutex_unlock(&fs_info->balance_mutex);
> ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
> - goto out;
> + goto out_bargs;
> }
>
> locked:

I think this is a better fix:

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7a6974e877f4..906ed1b93654 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4391,15 +4391,13 @@ static long btrfs_ioctl_balance(struct file
*file, void __user *arg)
goto again;
} else {
/* this is (2) */
- mutex_unlock(&fs_info->balance_mutex);
ret = -EINPROGRESS;
- goto out;
+ goto out_bargs;
}
} else {
/* this is (1) */
- mutex_unlock(&fs_info->balance_mutex);
ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
- goto out;
+ goto out_bargs;
}

locked:

2022-04-22 20:09:04

by Nikolay Borisov

Subject: Re: [PATCH] btrfs: Fix a memory leak in btrfs_ioctl_balance()

On 21.04.22 г. 14:21 ч., Nikolay Borisov wrote:
>
>
> On 21.04.22 г. 12:51 ч., Haowen Bai wrote:
>> Free "bargs" before return.
>>
>> Signed-off-by: Haowen Bai <[email protected]>
>> ---
>>   fs/btrfs/ioctl.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index f08233c2b0b2..d4c8bea914b7 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -4389,13 +4389,13 @@ static long btrfs_ioctl_balance(struct file
>> *file, void __user *arg)
>>               /* this is (2) */
>>               mutex_unlock(&fs_info->balance_mutex);
>>               ret = -EINPROGRESS;
>> -            goto out;
>> +            goto out_bargs;
>>           }
>>       } else {
>>           /* this is (1) */
>>           mutex_unlock(&fs_info->balance_mutex);
>>           ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
>> -        goto out;
>> +        goto out_bargs;
>>       }
>>   locked:
>
> I think this is a better fix:
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 7a6974e877f4..906ed1b93654 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4391,15 +4391,13 @@ static long btrfs_ioctl_balance(struct file
> *file, void __user *arg)
>                         goto again;
>                 } else {
>                         /* this is (2) */
> -                       mutex_unlock(&fs_info->balance_mutex);
>                         ret = -EINPROGRESS;
> -                       goto out;
> +                       goto out_bargs;
>                 }
>         } else {
>                 /* this is (1) */
> -               mutex_unlock(&fs_info->balance_mutex);
>                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
> -               goto out;
> +               goto out_bargs;
>         }
>
>  locked:
>


Actually to simplify further:

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7a6974e877f4..bbda55d41a06 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4353,6 +4353,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
bargs = memdup_user(arg, sizeof(*bargs));
if (IS_ERR(bargs)) {
ret = PTR_ERR(bargs);
+ bargs = NULL;
goto out;
}

@@ -4391,13 +4392,11 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
goto again;
} else {
/* this is (2) */
- mutex_unlock(&fs_info->balance_mutex);
ret = -EINPROGRESS;
goto out;
}
} else {
/* this is (1) */
- mutex_unlock(&fs_info->balance_mutex);
ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
goto out;
}
@@ -4406,7 +4405,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
if (bargs->flags & BTRFS_BALANCE_RESUME) {
if (!fs_info->balance_ctl) {
ret = -ENOTCONN;
- goto out_bargs;
+ goto out;
}

bctl = fs_info->balance_ctl;
@@ -4420,18 +4419,18 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)

if (bargs->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
ret = -EINVAL;
- goto out_bargs;
+ goto out;
}

if (fs_info->balance_ctl) {
ret = -EINPROGRESS;
- goto out_bargs;
+ goto out;
}

bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
if (!bctl) {
ret = -ENOMEM;
- goto out_bargs;
+ goto out;
}

memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
@@ -4457,12 +4456,11 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
}

kfree(bctl);
-out_bargs:
+out:
kfree(bargs);
mutex_unlock(&fs_info->balance_mutex);
if (need_unlock)
btrfs_exclop_finish(fs_info);
-out:
mnt_drop_write_file(file);
return ret;
}