Commit 705db3fd authored by Dave Chinner's avatar Dave Chinner Committed by Christoph Hellwig
Browse files

xfs: fix double free of inode 



If we fail to initialise the VFS inode in inode_init_always(),
it will call ->delete_inode internally resulting in the inode being
freed. Hence we need to delay the call to inode_init_always()
until after the XFS inode is sufficient set up to handle a
call to ->delete_inode, and then if that fails do not touch
the inode again at all as it has been freed.

Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent a6cb767e

fs/xfs/xfs_iget.c

+14 −9
Original line number Diff line number Diff line
@@ -69,15 +69,6 @@ xfs_inode_alloc( 
	ASSERT(!spin_is_locked(&ip->i_flags_lock));

	ASSERT(completion_done(&ip->i_flush));



	/*

	 * initialise the VFS inode here to get failures

	 * out of the way early.

	 */

	if (!inode_init_always(mp->m_super, VFS_I(ip))) {

		kmem_zone_free(xfs_inode_zone, ip);

		return NULL;

	}



	/* initialise the xfs inode */

	ip->i_ino = ino;

	ip->i_mount = mp;
@@ -113,6 +104,20 @@ xfs_inode_alloc( 
#ifdef XFS_DIR2_TRACE

	ip->i_dir_trace = ktrace_alloc(XFS_DIR2_KTRACE_SIZE, KM_NOFS);

#endif

	/*

	* Now initialise the VFS inode. We do this after the xfs_inode

	* initialisation as internal failures will result in ->destroy_inode

	* being called and that will pass down through the reclaim path and

	* free the XFS inode. This path requires the XFS inode to already be

	* initialised. Hence if this call fails, the xfs_inode has already

	* been freed and we should not reference it at all in the error

	* handling.

	*/

	if (!inode_init_always(mp->m_super, VFS_I(ip)))

		return NULL;



	/* prevent anyone from using this yet */

	VFS_I(ip)->i_state = I_NEW|I_LOCK;



	return ip;

}

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