[PATCH 2/2] ipc: WARN if trying to remove ipc object which is absent

[Alexander Mikhalitsyn]

Lets produce a warning if we trying to remove non-existing
IPC object from IPC namespace kht/idr structures.

This allows to catch possible bugs when ipc_rmid() function was
called with inconsistent struct ipc_ids*, struct kern_ipc_perm*
arguments.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Milton Miller <miltonm@xxxxxxx>
Cc: Jack Miller <millerjo@xxxxxxxxxx>
Cc: Pavel Tikhomirov <ptikhomirov@xxxxxxxxxxxxx>
Cc: Alexander Mikhalitsyn <alexander@xxxxxxxxxxxxx>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@xxxxxxxxxxxxx>
---
 ipc/util.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ipc/util.c b/ipc/util.c
index 0027e47626b7..45bb8ce6c42c 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -447,8 +447,8 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
 static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
 {
 	if (ipcp->key != IPC_PRIVATE)
-		rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
-				       ipc_kht_params);
+		WARN_ON(rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
+				       ipc_kht_params));
 }
 
 /**
@@ -498,7 +498,7 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
 {
 	int idx = ipcid_to_idx(ipcp->id);
 
-	idr_remove(&ids->ipcs_idr, idx);
+	WARN_ON(idr_remove(&ids->ipcs_idr, idx) != ipcp);
 	ipc_kht_remove(ids, ipcp);
 	ids->in_use--;
 	ipcp->deleted = true;
-- 
2.31.1