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ext4: check and assert if marking an no_delete evicting inode dirty 

commit 318cdc822c upstream.

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 WARN_ON_ONCE() to
check and detect this issue in advance.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220629112647.4141034-2-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Zhang Yi 2022-06-29 19:26:47 +08:00 committed by Greg Kroah-Hartman
parent 3711a8f7ec
commit 0c026f975d
1 changed files with 6 additions and 0 deletions
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6
fs/ext4/inode.c
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@ -335,6 +335,12 @@ stop_handle:
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.
*/
WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list));
if (!list_empty(&EXT4_I(inode)->i_fc_list))
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
ext4_clear_inode(inode); /* We must guarantee clearing of inode... */