From 2080205729edf2a59296f17081c9aa25a7ed6368 Mon Sep 17 00:00:00 2001 From: Dmitry Eremin Date: Tue, 23 Jul 2013 00:06:31 +0800 Subject: [PATCH] staging/lustre/ptlrpc: race in pinger (use-after-free situation) The race is result of use-after-free situation: ~ ptlrpc_stop_pinger() ~ ptlrpc_pinger_main() --------------------------------------------------------------- thread_set_flags(SVC_STOPPING) cfs_waitq_signal(pinger_thread) ... ... thread_set_flags(SVC_STOPPED) l_wait_event(thread_is_stopped) OBD_FREE_PTR(pinger_thread) ... cfs_waitq_signal(pinger_thread) --------------------------------------------------------------- The memory used by pinger_thread might have been freed and reallocated to something else, when ptlrpc_pinger_main() used it in cvs_waitq_signal(). Signed-off-by: Li Wei Signed-off-by: Dmitry Eremin Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3032 Lustre-change: http://review.whamcloud.com/6040 Reviewed-by: Faccini Bruno Reviewed-by: Mike Pershin Reviewed-by: Andreas Dilger Signed-off-by: Peng Tao Signed-off-by: Andreas Dilger Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/ptlrpc/pinger.c | 39 ++++++++----------- 1 file changed, 16 insertions(+), 23 deletions(-) diff --git a/drivers/staging/lustre/lustre/ptlrpc/pinger.c b/drivers/staging/lustre/lustre/ptlrpc/pinger.c index ef5269aee0de..f521251a1a6e 100644 --- a/drivers/staging/lustre/lustre/ptlrpc/pinger.c +++ b/drivers/staging/lustre/lustre/ptlrpc/pinger.c @@ -369,7 +369,7 @@ static int ptlrpc_pinger_main(void *arg) return 0; } -static struct ptlrpc_thread *pinger_thread = NULL; +static struct ptlrpc_thread pinger_thread; int ptlrpc_start_pinger(void) { @@ -377,29 +377,25 @@ int ptlrpc_start_pinger(void) int rc; ENTRY; - if (pinger_thread != NULL) + if (!thread_is_init(&pinger_thread) && + !thread_is_stopped(&pinger_thread)) RETURN(-EALREADY); - OBD_ALLOC_PTR(pinger_thread); - if (pinger_thread == NULL) - RETURN(-ENOMEM); - init_waitqueue_head(&pinger_thread->t_ctl_waitq); + init_waitqueue_head(&pinger_thread.t_ctl_waitq); init_waitqueue_head(&suspend_timeouts_waitq); - strcpy(pinger_thread->t_name, "ll_ping"); + strcpy(pinger_thread.t_name, "ll_ping"); /* CLONE_VM and CLONE_FILES just avoid a needless copy, because we * just drop the VM and FILES in cfs_daemonize_ctxt() right away. */ rc = PTR_ERR(kthread_run(ptlrpc_pinger_main, - pinger_thread, pinger_thread->t_name)); + &pinger_thread, pinger_thread.t_name)); if (IS_ERR_VALUE(rc)) { CERROR("cannot start thread: %d\n", rc); - OBD_FREE(pinger_thread, sizeof(*pinger_thread)); - pinger_thread = NULL; RETURN(rc); } - l_wait_event(pinger_thread->t_ctl_waitq, - thread_is_running(pinger_thread), &lwi); + l_wait_event(pinger_thread.t_ctl_waitq, + thread_is_running(&pinger_thread), &lwi); if (suppress_pings) CWARN("Pings will be suppressed at the request of the " @@ -419,20 +415,17 @@ int ptlrpc_stop_pinger(void) int rc = 0; ENTRY; - if (pinger_thread == NULL) + if (!thread_is_init(&pinger_thread) && + !thread_is_stopped(&pinger_thread)) RETURN(-EALREADY); ptlrpc_pinger_remove_timeouts(); - mutex_lock(&pinger_mutex); - thread_set_flags(pinger_thread, SVC_STOPPING); - wake_up(&pinger_thread->t_ctl_waitq); - mutex_unlock(&pinger_mutex); + thread_set_flags(&pinger_thread, SVC_STOPPING); + wake_up(&pinger_thread.t_ctl_waitq); - l_wait_event(pinger_thread->t_ctl_waitq, - thread_is_stopped(pinger_thread), &lwi); + l_wait_event(pinger_thread.t_ctl_waitq, + thread_is_stopped(&pinger_thread), &lwi); - OBD_FREE_PTR(pinger_thread); - pinger_thread = NULL; RETURN(rc); } @@ -617,8 +610,8 @@ int ptlrpc_pinger_remove_timeouts(void) void ptlrpc_pinger_wake_up() { - thread_add_flags(pinger_thread, SVC_EVENT); - wake_up(&pinger_thread->t_ctl_waitq); + thread_add_flags(&pinger_thread, SVC_EVENT); + wake_up(&pinger_thread.t_ctl_waitq); } /* Ping evictor thread */ -- 2.30.2