From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751789AbcFTFN3 (ORCPT ); Mon, 20 Jun 2016 01:13:29 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:37827 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751959AbcFTFL7 (ORCPT ); Mon, 20 Jun 2016 01:11:59 -0400 X-Original-SENDERIP: 156.147.1.126 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: peterz@infradead.org, mingo@kernel.org Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, walken@google.com, ak@suse.de, tglx@inhelltoy.tec.linutronix.de Subject: [RFC 03/12] lockdep: Make check_prev_add can use a stack_trace of other context Date: Mon, 20 Jun 2016 13:55:18 +0900 Message-Id: <1466398527-1122-4-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1466398527-1122-1-git-send-email-byungchul.park@lge.com> References: <1466398527-1122-1-git-send-email-byungchul.park@lge.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, check_prev_add() can only save its current context's stack trace. But it would be useful if a seperated stack_trace can be taken and used in check_prev_add(). Crossrelease feature can use check_prev_add() with another context's stack_trace. Signed-off-by: Byungchul Park --- kernel/locking/lockdep.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 4d51208..c596bef 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1822,7 +1822,8 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, */ static int check_prev_add(struct task_struct *curr, struct held_lock *prev, - struct held_lock *next, int distance, int *stack_saved) + struct held_lock *next, int distance, int *stack_saved, + struct stack_trace *own_trace) { struct lock_list *entry; int ret; @@ -1883,7 +1884,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, } } - if (!*stack_saved) { + if (!own_trace && stack_saved && !*stack_saved) { if (!save_trace(&trace)) return 0; *stack_saved = 1; @@ -1895,14 +1896,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, */ ret = add_lock_to_list(hlock_class(prev), hlock_class(next), &hlock_class(prev)->locks_after, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, own_trace ?: &trace); if (!ret) return 0; ret = add_lock_to_list(hlock_class(next), hlock_class(prev), &hlock_class(next)->locks_before, - next->acquire_ip, distance, &trace); + next->acquire_ip, distance, own_trace ?: &trace); if (!ret) return 0; @@ -1911,7 +1912,8 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, */ if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { /* We drop graph lock, so another thread can overwrite trace. */ - *stack_saved = 0; + if (stack_saved) + *stack_saved = 0; graph_unlock(); printk("\n new dependency: "); print_lock_name(hlock_class(prev)); @@ -1960,8 +1962,8 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next) * added: */ if (hlock->read != 2 && hlock->check) { - if (!check_prev_add(curr, hlock, next, - distance, &stack_saved)) + if (!check_prev_add(curr, hlock, next, distance, + &stack_saved, NULL)) return 0; /* * Stop after the first non-trylock entry, -- 1.9.1