diff options
author | Filipe Manana <fdmanana@suse.com> | 2024-11-04 12:11:15 +0000 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2024-11-07 02:07:53 +0100 |
commit | c9a75ec45f1111ef530ab186c2a7684d0a0c9245 (patch) | |
tree | b93f61c7060a42cccc51fa057c460ce6f00eec75 /fs | |
parent | cda7163d4e3d99db93aa38f0e825b8433c7a8452 (diff) |
btrfs: reinitialize delayed ref list after deleting it from the list
At insert_delayed_ref() if we need to update the action of an existing
ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's
ref_add_list using list_del(), which leaves the ref's add_list member
not reinitialized, as list_del() sets the next and prev members of the
list to LIST_POISON1 and LIST_POISON2, respectively.
If later we end up calling drop_delayed_ref() against the ref, which can
happen during merging or when destroying delayed refs due to a transaction
abort, we can trigger a crash since at drop_delayed_ref() we call
list_empty() against the ref's add_list, which returns false since
the list was not reinitialized after the list_del() and as a consequence
we call list_del() again at drop_delayed_ref(). This results in an
invalid list access since the next and prev members are set to poison
pointers, resulting in a splat if CONFIG_LIST_HARDENED and
CONFIG_DEBUG_LIST are set or invalid poison pointer dereferences
otherwise.
So fix this by deleting from the list with list_del_init() instead.
Fixes: 1d57ee941692 ("btrfs: improve delayed refs iterations")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/delayed-ref.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 115b90d29b1d..65d841d7142c 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -649,7 +649,7 @@ static bool insert_delayed_ref(struct btrfs_trans_handle *trans, &href->ref_add_list); else if (ref->action == BTRFS_DROP_DELAYED_REF) { ASSERT(!list_empty(&exist->add_list)); - list_del(&exist->add_list); + list_del_init(&exist->add_list); } else { ASSERT(0); } |