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locks: fix error in locks_move_blocks()

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After moving all requests from
   fl->fl_blocked_requests
to
   new->fl_blocked_requests

it is nonsensical to do anything to all the remaining elements, there
aren't any.  This should do something to all the requests that have been
moved. For simplicity, it does it to all requests in the target list.

Setting "f->fl_blocker = new" to all members of new->fl_blocked_requests
is "obviously correct" as it preserves the invariant of the linkage
among requests.

Reported-by: syzbot+239d99847eb49ecb3899@syzkaller.appspotmail.com
Fixes: 5946c4319e ("fs/locks: allow a lock request to block other requests.")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
This commit is contained in:
NeilBrown 2019-01-03 11:04:08 +11:00 committed by Jeff Layton
parent 8e143b90e4
commit bf77ae4c98
1 changed files with 1 additions and 1 deletions
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2
fs/locks.c
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@ -453,7 +453,7 @@ static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
return;
spin_lock(&blocked_lock_lock);
list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests);
list_for_each_entry(f, &fl->fl_blocked_requests, fl_blocked_member)
list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member)
f->fl_blocker = new;
spin_unlock(&blocked_lock_lock);
}