Unverified Commit e9d50b78 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "fs: add iput_not_last()" 

Add iput_not_last() and switch landlock over to it to remove
false-positives from might_sleep() annotations in iput().

Link: https://patch.msgid.link/20251105212025.807549-1-mjguzik@gmail.com

* patches from https://patch.msgid.link/20251105212025.807549-1-mjguzik@gmail.com

:
  landlock: fix splats from iput() after it started calling might_sleep()
  fs: add iput_not_last()

Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 3cd1548a 56325e8c

fs/inode.c

+12 −0
Original line number Diff line number Diff line
@@ -1967,6 +1967,18 @@ void iput(struct inode *inode) 
}

EXPORT_SYMBOL(iput);



/**

 *	iput_not_last	- put an inode assuming this is not the last reference

 *	@inode: inode to put

 */

void iput_not_last(struct inode *inode)

{

	VFS_BUG_ON_INODE(atomic_read(&inode->i_count) < 2, inode);



	WARN_ON(atomic_sub_return(1, &inode->i_count) == 0);

}

EXPORT_SYMBOL(iput_not_last);



#ifdef CONFIG_BLOCK

/**

 *	bmap	- find a block number in a file

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -2824,6 +2824,7 @@ extern int current_umask(void); 


extern void ihold(struct inode * inode);

extern void iput(struct inode *);

void iput_not_last(struct inode *);

int inode_update_timestamps(struct inode *inode, int flags);

int generic_update_time(struct inode *, int);

security/landlock/fs.c

+3 −4
Original line number Diff line number Diff line
@@ -1335,11 +1335,10 @@ static void hook_sb_delete(struct super_block *const sb) 
			 * At this point, we own the ihold() reference that was

			 * originally set up by get_inode_object() and the

			 * __iget() reference that we just set in this loop

			 * walk.  Therefore the following call to iput() will

			 * not sleep nor drop the inode because there is now at

			 * least two references to it.

			 * walk.  Therefore there are at least two references

			 * on the inode.

			 */

			iput(inode);

			iput_not_last(inode);

		} else {

			spin_unlock(&object->lock);

			rcu_read_unlock();