ipc/util.c: sysvipc_find_ipc() incorrectly updates position index
Commit 89163f93c6f9 ("ipc/util.c: sysvipc_find_ipc() should increase
position index") 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
Whenever an IPC item with a low id is deleted, the items with higher ids
are duplicated, as if filling a hole.
new_pos should jump through hole of unused ids, pos can be updated
inside "for" cycle.
Fixes: 89163f93c6f9 ("ipc/util.c: sysvipc_find_ipc() should increase position index")
Reported-by: Andreas Schwab <[email protected]>
Reported-by: Randy Dunlap <[email protected]>
Signed-off-by: Vasily Averin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Waiman Long <[email protected]>
Cc: NeilBrown <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Oberparleiter <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Manfred Spraul <[email protected]>
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed
