| Message ID | 20210116090910.5671-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hugetlbfs: make BUG_ON(!inode) takes effect in hugetlbfs_setattr | expand |
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 >
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 >> > . >
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;
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(-)