From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34266C433ED for ; Sat, 24 Apr 2021 14:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 059A2613C4 for ; Sat, 24 Apr 2021 14:28:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233148AbhDXO3O (ORCPT ); Sat, 24 Apr 2021 10:29:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230211AbhDXO3K (ORCPT ); Sat, 24 Apr 2021 10:29:10 -0400 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A70AAC061574 for ; Sat, 24 Apr 2021 07:28:30 -0700 (PDT) Received: by mail-pg1-x531.google.com with SMTP id d10so37110584pgf.12 for ; Sat, 24 Apr 2021 07:28:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=fTPHG3ZQxyB7UgXq6RIgSrPKdFPuuTXRg5DyuPKAK+Y=; b=Z4f8A1pgTdnYeGDwMpAVGp0ANw7J6FCB5NT7v7t2J4FrgeFfUtmeUAsPIMyKiM+taR IkKW+q+XQs/flRjn46p0JEa5BXJ56dyWcgl0WZ5+iwryjbW+BpkD3sDPXn1snfRtuEXZ jNlESlEC5JAG9Xy9XdvutSnejlCqtbLHt6axrr1rRjbmzR1l+taRPPEKnAE7ZuV/xsp1 96h3kZJooNoh55+n5pSFrcrzYXScvPnSsIY3ypka68GVXuSQQ0xngqYoUB8ALbe5jPcG vu5KvKI9cpMMadDeJ+95yIxyAEXjq62OlEmQiYgrMd8j0ykGlWsmD2z5nN5tKbyiDT65 epIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=fTPHG3ZQxyB7UgXq6RIgSrPKdFPuuTXRg5DyuPKAK+Y=; b=MwV8Zv+1lCWhnjO33Mas65lj+nzzntflknwskg6E+BqNvqF612iB6EjmxZxOk87vs1 7yAj0KpKjv7l1FaJjDkX4nTNUzTrcMTTIqQatWmp/pbcrClaRcUxH/bNjN6nDniT8z2M mCKJAs4dsrdOZqA4JnffBgGuB8IEdZeN7kkeAhwW0xYUQpbW+nNj0KUetFbI34yctSKv agv1WVAvx7MWu1HsVm2R62ANvf7oZZ9IXhKji6e2s4k+G0v8/4mvywxdwoibRbs1qst7 /J9Kd3yfKj8A35qtE8Gd5SER8c3C7BYCd+1P9S1eCE5j8lyqxt5iyGJ8TnlWoFGQoUaV e6tQ== X-Gm-Message-State: AOAM531Rl8SUuhTQdvkQ8Kmpn3L+/cdQjYNT7D5Knre+NtY5AaHlGNSv hPM0xObTckgIC86lEuMkCBk= X-Google-Smtp-Source: ABdhPJxssnvTRDKAPb3Hm5AdHBbOCMP/gfE5aNi3TIC6Ow4QeiX3LqvKq5GfZUJIccF/ds71L8fdLw== X-Received: by 2002:a05:6a00:1aca:b029:25a:b810:94c7 with SMTP id f10-20020a056a001acab029025ab81094c7mr8816605pfv.15.1619274510313; Sat, 24 Apr 2021 07:28:30 -0700 (PDT) Received: from hyeyoo.42seoul.kr ([121.135.181.35]) by smtp.gmail.com with ESMTPSA id p126sm7547455pga.86.2021.04.24.07.28.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 24 Apr 2021 07:28:30 -0700 (PDT) From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: peterz@infradead.org, mingo@redhat.com, will@kernel.org Cc: linux-kernel@vger.kernel.org, Hyeonggon Yoo <42.hyeyoo@gmail.com> Subject: [PATCH] kernel/locking: make __down_common use flags previously saved Date: Sat, 24 Apr 2021 23:28:23 +0900 Message-Id: <20210424142823.3896-1-42.hyeyoo@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org down, down_interruptible, down_killable, and down_timeout call raw_spin_lock_irqsave that saves current status to flags. but in __down_common, that is called by functions above, calls raw_spin_lock_irq and raw_spin_unlock_irq regardless of flags previously saved. this mismatch can potentially cause problem. so made __down_common use raw_spin_lock_irqsave and raw_spin_unlock_irqrestore. Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> --- kernel/locking/semaphore.c | 42 +++++++++++++++++++++----------------- 1 file changed, 23 insertions(+), 19 deletions(-) diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c index 9aa855a96c4a..0ea174223441 100644 --- a/kernel/locking/semaphore.c +++ b/kernel/locking/semaphore.c @@ -33,10 +33,10 @@ #include #include -static noinline void __down(struct semaphore *sem); -static noinline int __down_interruptible(struct semaphore *sem); -static noinline int __down_killable(struct semaphore *sem); -static noinline int __down_timeout(struct semaphore *sem, long timeout); +static noinline void __down(struct semaphore *sem, unsigned long flags); +static noinline int __down_interruptible(struct semaphore *sem, unsigned long flags); +static noinline int __down_killable(struct semaphore *sem, unsigned long flags); +static noinline int __down_timeout(struct semaphore *sem, long timeout, unsigned long flags); static noinline void __up(struct semaphore *sem); /** @@ -58,7 +58,7 @@ void down(struct semaphore *sem) if (likely(sem->count > 0)) sem->count--; else - __down(sem); + __down(sem, flags); raw_spin_unlock_irqrestore(&sem->lock, flags); } EXPORT_SYMBOL(down); @@ -81,7 +81,7 @@ int down_interruptible(struct semaphore *sem) if (likely(sem->count > 0)) sem->count--; else - result = __down_interruptible(sem); + result = __down_interruptible(sem, flags); raw_spin_unlock_irqrestore(&sem->lock, flags); return result; @@ -107,7 +107,7 @@ int down_killable(struct semaphore *sem) if (likely(sem->count > 0)) sem->count--; else - result = __down_killable(sem); + result = __down_killable(sem, flags); raw_spin_unlock_irqrestore(&sem->lock, flags); return result; @@ -161,7 +161,7 @@ int down_timeout(struct semaphore *sem, long timeout) if (likely(sem->count > 0)) sem->count--; else - result = __down_timeout(sem, timeout); + result = __down_timeout(sem, timeout, flags); raw_spin_unlock_irqrestore(&sem->lock, flags); return result; @@ -202,7 +202,7 @@ struct semaphore_waiter { * 'timeout' parameter for the cases without timeouts. */ static inline int __sched __down_common(struct semaphore *sem, long state, - long timeout) + long timeout, unsigned long flags) { struct semaphore_waiter waiter; @@ -216,9 +216,9 @@ static inline int __sched __down_common(struct semaphore *sem, long state, if (unlikely(timeout <= 0)) goto timed_out; __set_current_state(state); - raw_spin_unlock_irq(&sem->lock); + raw_spin_unlock_irqrestore(&sem->lock, flags); timeout = schedule_timeout(timeout); - raw_spin_lock_irq(&sem->lock); + raw_spin_lock_irqsave(&sem->lock, flags); if (waiter.up) return 0; } @@ -232,24 +232,28 @@ static inline int __sched __down_common(struct semaphore *sem, long state, return -EINTR; } -static noinline void __sched __down(struct semaphore *sem) +static noinline void __sched __down(struct semaphore *sem, unsigned long flags) { - __down_common(sem, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); + __down_common(sem, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT, flags); } -static noinline int __sched __down_interruptible(struct semaphore *sem) +static noinline int __sched __down_interruptible(struct semaphore *sem, + unsigned long flags) { - return __down_common(sem, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); + return __down_common(sem, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT, + flags); } -static noinline int __sched __down_killable(struct semaphore *sem) +static noinline int __sched __down_killable(struct semaphore *sem, + unsigned long flags) { - return __down_common(sem, TASK_KILLABLE, MAX_SCHEDULE_TIMEOUT); + return __down_common(sem, TASK_KILLABLE, MAX_SCHEDULE_TIMEOUT, flags); } -static noinline int __sched __down_timeout(struct semaphore *sem, long timeout) +static noinline int __sched __down_timeout(struct semaphore *sem, + long timeout, unsigned long flags) { - return __down_common(sem, TASK_UNINTERRUPTIBLE, timeout); + return __down_common(sem, TASK_UNINTERRUPTIBLE, timeout, flags); } static noinline void __sched __up(struct semaphore *sem) -- 2.25.1