Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755811AbcCBCuU (ORCPT ); Tue, 1 Mar 2016 21:50:20 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:55586 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260AbcCBCuS (ORCPT ); Tue, 1 Mar 2016 21:50:18 -0500 From: MaJun To: , , , , , , , , , , Subject: [PATCH] Change the spin_lock/unlock_irq interface in proc_alloc_inum() function Date: Wed, 2 Mar 2016 10:47:59 +0800 Message-ID: <1456886879-28128-1-git-send-email-majun258@huawei.com> X-Mailer: git-send-email 1.9.5.msysgit.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.177.235.245] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090201.56D65470.0072,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: e5455d5ecedcfff138d64c06edda8321 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1361 Lines: 54 From: Ma Jun The spin_lock/unlock_irq interface is not safe when this function is called at some case which need irq disabled. For example: spin_lock_irqsave() | request_irq() --> proc_alloc_inum() | spin_unlock_irqrestore() Reported-by: Fan Jinke Signed-off-by: Ma Jun --- fs/proc/generic.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index ff3ffc7..4fc1502 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -191,23 +191,24 @@ int proc_alloc_inum(unsigned int *inum) { unsigned int i; int error; + unsigned long flags; retry: if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL)) return -ENOMEM; - spin_lock_irq(&proc_inum_lock); + spin_lock_irqsave(&proc_inum_lock, flags); error = ida_get_new(&proc_inum_ida, &i); - spin_unlock_irq(&proc_inum_lock); + spin_unlock_irqrestore(&proc_inum_lock, flags); if (error == -EAGAIN) goto retry; else if (error) return error; if (i > UINT_MAX - PROC_DYNAMIC_FIRST) { - spin_lock_irq(&proc_inum_lock); + spin_lock_irqsave(&proc_inum_lock, flags); ida_remove(&proc_inum_ida, i); - spin_unlock_irq(&proc_inum_lock); + spin_unlock_irqrestore(&proc_inum_lock, flags); return -ENOSPC; } *inum = PROC_DYNAMIC_FIRST + i; -- 1.7.1