* [PATCH] hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr
@ 2021-01-16 9:09 Miaohe Lin
2021-01-18 7:59 ` Muchun Song
0 siblings, 1 reply; 3+ messages in thread
From: Miaohe Lin @ 2021-01-16 9:09 UTC (permalink / raw)
To: mike.kravetz; +Cc: linux-mm, linux-kernel, linmiaohe
When we reach here with inode = NULL, we should have crashed as inode has
already been dereferenced via hstate_inode. In order to make BUG_ON(!inode)
takes effect, we should defer initializing hstate until we really need it.
Also do this for hugetlbfs_inode_info as it's only used when ia_valid is
verified with ATTR_SIZE.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
fs/hugetlbfs/inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 740693d7f255..9b221b87fbea 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -755,10 +755,8 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
- struct hstate *h = hstate_inode(inode);
int error;
unsigned int ia_valid = attr->ia_valid;
- struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
BUG_ON(!inode);
@@ -767,6 +765,8 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
return error;
if (ia_valid & ATTR_SIZE) {
+ struct hstate *h = hstate_inode(inode);
+ struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
loff_t oldsize = inode->i_size;
loff_t newsize = attr->ia_size;
--
2.19.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr
2021-01-16 9:09 [PATCH] hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr Miaohe Lin
@ 2021-01-18 7:59 ` Muchun Song
2021-01-18 8:48 ` Miaohe Lin
0 siblings, 1 reply; 3+ messages in thread
From: Muchun Song @ 2021-01-18 7:59 UTC (permalink / raw)
To: Miaohe Lin; +Cc: mike.kravetz, linux-mm, linux-kernel
On Sat, Jan 16, 2021 at 5:11 PM Miaohe Lin <linmiaohe@huawei.com> wrote:
>
> When we reach here with inode = NULL, we should have crashed as inode has
> already been dereferenced via hstate_inode. In order to make BUG_ON(!inode)
> takes effect, we should defer initializing hstate until we really need it.
> Also do this for hugetlbfs_inode_info as it's only used when ia_valid is
> verified with ATTR_SIZE.
>
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---
> fs/hugetlbfs/inode.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
> index 740693d7f255..9b221b87fbea 100644
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -755,10 +755,8 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
> static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
> {
> struct inode *inode = d_inode(dentry);
> - struct hstate *h = hstate_inode(inode);
If inode == NULL, it will panic here when we access inode->i_sb.
I have seen many other file system implementations about setattr,
they all think that d_inode() will return a non-NULL pointer. So
I prefer to just remove the BUG_ON().
Thanks.
> int error;
> unsigned int ia_valid = attr->ia_valid;
> - struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
>
> BUG_ON(!inode);
>
> @@ -767,6 +765,8 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
> return error;
>
> if (ia_valid & ATTR_SIZE) {
> + struct hstate *h = hstate_inode(inode);
> + struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
> loff_t oldsize = inode->i_size;
> loff_t newsize = attr->ia_size;
>
> --
> 2.19.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr
2021-01-18 7:59 ` Muchun Song
@ 2021-01-18 8:48 ` Miaohe Lin
0 siblings, 0 replies; 3+ messages in thread
From: Miaohe Lin @ 2021-01-18 8:48 UTC (permalink / raw)
To: Muchun Song; +Cc: mike.kravetz, linux-mm, linux-kernel
Hi:
On 2021/1/18 15:59, Muchun Song wrote:
> On Sat, Jan 16, 2021 at 5:11 PM Miaohe Lin <linmiaohe@huawei.com> wrote:
>>
>> When we reach here with inode = NULL, we should have crashed as inode has
>> already been dereferenced via hstate_inode. In order to make BUG_ON(!inode)
>> takes effect, we should defer initializing hstate until we really need it.
>> Also do this for hugetlbfs_inode_info as it's only used when ia_valid is
>> verified with ATTR_SIZE.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>> fs/hugetlbfs/inode.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
>> index 740693d7f255..9b221b87fbea 100644
>> --- a/fs/hugetlbfs/inode.c
>> +++ b/fs/hugetlbfs/inode.c
>> @@ -755,10 +755,8 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
>> static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
>> {
>> struct inode *inode = d_inode(dentry);
>> - struct hstate *h = hstate_inode(inode);
>
> If inode == NULL, it will panic here when we access inode->i_sb.
> I have seen many other file system implementations about setattr,
> they all think that d_inode() will return a non-NULL pointer. So
> I prefer to just remove the BUG_ON().
>
Sounds reasonable. Will do it in v2. Many thanks.
> Thanks.
>
>
>> int error;
>> unsigned int ia_valid = attr->ia_valid;
>> - struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
>>
>> BUG_ON(!inode);
>>
>> @@ -767,6 +765,8 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
>> return error;
>>
>> if (ia_valid & ATTR_SIZE) {
>> + struct hstate *h = hstate_inode(inode);
>> + struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
>> loff_t oldsize = inode->i_size;
>> loff_t newsize = attr->ia_size;
>>
>> --
>> 2.19.1
>>
> .
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-01-16 9:09 [PATCH] hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr Miaohe Lin
2021-01-18 7:59 ` Muchun Song
2021-01-18 8:48 ` Miaohe Lin
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