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From:   Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
To:     linux-kernel@vger.kernel.org
Cc:     Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Milton Miller <miltonm@bga.com>,
        Jack Miller <millerjo@us.ibm.com>,
        Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
        Alexander Mikhalitsyn <alexander@mihalicyn.com>
Subject: [PATCH 2/2] ipc: WARN if trying to remove ipc object which is absent
Date:   Tue,  6 Jul 2021 16:22:59 +0300
Message-Id: <20210706132259.71740-3-alexander.mikhalitsyn@virtuozzo.com>
In-Reply-To: <20210706132259.71740-1-alexander.mikhalitsyn@virtuozzo.com>
References: <20210706132259.71740-1-alexander.mikhalitsyn@virtuozzo.com>
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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@linux-foundation.org>
Cc: Milton Miller <miltonm@bga.com>
Cc: Jack Miller <millerjo@us.ibm.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
---
 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