staging/lustre/ptlrpc: Race between start and stop service threads
authorHiroya Nozaki <nozaki.hiroya@jp.fujitsu.com>
Mon, 22 Jul 2013 16:06:48 +0000 (00:06 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 23 Jul 2013 20:35:50 +0000 (13:35 -0700)
commit5be8e0702619eb3e77ec41c3b8825d0bbdfd8cda
tree9da427838c4d2f1e42becfc7180a42d080bdd538
parenta55e0f44cf360a2f466b4599ec107fae4bafae64
staging/lustre/ptlrpc: Race between start and stop service threads

When ptlrpc_start_thread fails to create a new thread, it will
finalize and free a struct ptlrpc_thread created and used here.
Considering this, it can be a problem when ptlrpc_svcpt_stop_thread
is driven and handles the struct ptlrpc_thread right after or right
before failure of cfs_create_thread. Because this situation let
the both of ptlrpc_start_thread and ptlrpc_svcpt_stop_threads
access the freed ptlrpc_thread and cause OS panic. Or, it may
happen that ptlrpc_svcpt_stop_threads waits forever holding an
already-freed waitq.

This patch adds an error handling into ptlrpc_start_thread to fix
this problem.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2889
Lustre-change: http://review.whamcloud.com/5552
Signed-off-by: Hiroya Nozaki <nozaki.hiroya@jp.fujitsu.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Nikitas Angelinas <nikitas_angelinas@xyratex.com>
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/ptlrpc/service.c