From bf77ae4c98d721a9aae3840970d46669a78e034a Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.com>
Date: Thu, 3 Jan 2019 11:04:08 +1100
Subject: [PATCH] locks: fix error in locks_move_blocks()
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: 5946c4319ebb ("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>
---
fs/locks.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/locks.c b/fs/locks.c
index f0b24d98f36be..ff6af2c326012 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -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);
}
--
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