On Wed 29-06-22 10:29:40, Zhang Yi wrote: > In ext4_evict_inode(), if we evicting an inode in the 'no_delete' path, > it cannot be raced by another mark_inode_dirty(). If it happens, > someone else may accidentally dirty it without holding inode refcount > and probably cause use-after-free issues in the writeback procedure. > It's indiscoverable and hard to debug, so add an ASSERT to check and > detect this issue in advance. > > Suggested-by: Jan Kara <jack@xxxxxxx> > Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx> > --- > fs/ext4/inode.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 702cc208689a..2ba74412aa89 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -333,6 +333,12 @@ void ext4_evict_inode(struct inode *inode) > ext4_xattr_inode_array_free(ea_inode_array); > return; > no_delete: > + /* > + * Check out some where else accidentally dirty the evicting inode, > + * which may probably cause inode use-after-free issues later. > + */ > + ASSERT(list_empty_careful(&inode->i_io_list)); ASSERT() is harsh as it will take the kernel down. Just use WARN_ON_ONCE() to notify us of the coming problems :). Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
