From: Andreas Schwab <schwab@suse.de>
To: Vasily Averin <vvs@virtuozzo.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
NeilBrown <neilb@suse.com>, Waiman Long <longman@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Oberparleiter <oberpar@linux.ibm.com>
Subject: Re: [PATCH 7/7] sysvipc_find_ipc should increase position index
Date: Tue, 05 May 2020 18:13:08 +0200 [thread overview]
Message-ID: <mvm4ksupdgr.fsf@suse.de> (raw)
In-Reply-To: <b7a20945-e315-8bb0-21e6-3875c14a8494@virtuozzo.com> (Vasily Averin's message of "Fri, 24 Jan 2020 10:03:12 +0300")
I think this is causing this bug (seen on 5.6.8):
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
# ipcmk -Q
Message queue id: 0
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
0x82db8127 0 root 644 0 0
# ipcmk -Q
Message queue id: 1
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
0x82db8127 0 root 644 0 0
0x76d1fb2a 1 root 644 0 0
# ipcrm -q 0
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
0x76d1fb2a 1 root 644 0 0
0x76d1fb2a 1 root 644 0 0
# ipcmk -Q
Message queue id: 2
# ipcrm -q 2
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
0x76d1fb2a 1 root 644 0 0
0x76d1fb2a 1 root 644 0 0
# ipcmk -Q
Message queue id: 3
# ipcrm -q 1
# ipcs -q
------ Message Queues --------
key msqid owner perms used-bytes messages
0x7c982867 3 root 644 0 0
0x7c982867 3 root 644 0 0
0x7c982867 3 root 644 0 0
0x7c982867 3 root 644 0 0
As you can see, whenever an IPC item with a low id is deleted, the items
with higher ids are duplicated, as if filling a hole.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
next prev parent reply other threads:[~2020-05-05 16:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 7:03 [PATCH 7/7] sysvipc_find_ipc should increase position index Vasily Averin
2020-01-24 16:26 ` Waiman Long
2020-02-25 6:35 ` Vasily Averin
2020-05-05 16:13 ` Andreas Schwab [this message]
2020-05-06 5:03 ` Vasily Averin
2020-05-06 6:25 ` [PATCH] ipc/util.c: sysvipc_find_ipc() incorrectly updates " Vasily Averin
2020-05-06 15:59 ` Waiman Long
2020-05-07 12:29 ` Vasily Averin
2020-05-08 0:02 ` Andrew Morton
2020-05-08 3:36 ` Matthew Wilcox
2020-05-08 6:07 ` Vasily Averin
2020-05-08 10:01 ` Vasily Averin
2020-05-12 9:21 ` Jiri Slaby
2020-05-12 15:45 ` Vasily Averin
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