| Message ID | 20200921191243.27833-1-a.dewar@sussex.ac.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: Fix potential null pointer deref | expand |
On 9/21/20 3:12 PM, Alex Dewar wrote: > In btrfs_destroy_inode(), the variable root may be NULL, but the check > for this takes place after its value has already been dereferenced to > access its fs_info member. Move the dereference operation to later in > the function. > > Fixes: a6dbd429d8dd ("Btrfs: fix panic when trying to destroy a newly allocated") > Addresses-Coverity: CID 1497103: Null pointer dereferences (REVERSE_INULL) > Signed-off-by: Alex Dewar <a.dewar@sussex.ac.uk> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Thanks, Josef
On Mon, Sep 21, 2020 at 08:12:44PM +0100, Alex Dewar wrote: > In btrfs_destroy_inode(), the variable root may be NULL, but the check > for this takes place after its value has already been dereferenced to > access its fs_info member. Move the dereference operation to later in > the function. > > Fixes: a6dbd429d8dd ("Btrfs: fix panic when trying to destroy a newly allocated") > Addresses-Coverity: CID 1497103: Null pointer dereferences (REVERSE_INULL) > Signed-off-by: Alex Dewar <a.dewar@sussex.ac.uk> For some reason my replies did not get to linux-btrfs@, so for the record the changes has been folded to the patch "btrfs: clean BTRFS_I usage in btrfs_destroy_inode".
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index a5dae53c1e27..8f230b7bfe65 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8648,7 +8648,6 @@ void btrfs_destroy_inode(struct inode *vfs_inode) struct btrfs_ordered_extent *ordered; struct btrfs_inode *inode = BTRFS_I(vfs_inode); struct btrfs_root *root = inode->root; - struct btrfs_fs_info *fs_info = root->fs_info; WARN_ON(!hlist_empty(&vfs_inode->i_dentry)); WARN_ON(vfs_inode->i_data.nrpages); @@ -8673,7 +8672,7 @@ void btrfs_destroy_inode(struct inode *vfs_inode) if (!ordered) break; else { - btrfs_err(fs_info, + btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup", ordered->file_offset, ordered->num_bytes); btrfs_remove_ordered_extent(inode, ordered);
In btrfs_destroy_inode(), the variable root may be NULL, but the check for this takes place after its value has already been dereferenced to access its fs_info member. Move the dereference operation to later in the function. Fixes: a6dbd429d8dd ("Btrfs: fix panic when trying to destroy a newly allocated") Addresses-Coverity: CID 1497103: Null pointer dereferences (REVERSE_INULL) Signed-off-by: Alex Dewar <a.dewar@sussex.ac.uk> --- fs/btrfs/inode.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)