From: viro@ZenIV.linux.org.uk (Al Viro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] Change the spin_lock/unlock_irq interface in proc_alloc_inum() function
Date: Wed, 2 Mar 2016 03:09:41 +0000 [thread overview]
Message-ID: <20160302030941.GH17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1456886879-28128-1-git-send-email-majun258@huawei.com>
On Wed, Mar 02, 2016 at 10:47:59AM +0800, MaJun wrote:
> From: Ma Jun <majun258@huawei.com>
>
> 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()
Do you even read your own patch?
> if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
^^^^^^^^^^
This.
It can block. You *can't* call that under spin_lock_irqsave(). At all.
You also can't do request_irq() under a spinlock, no matter whether you
disable irqs or not - it also blocks. So does proc_mkdir(), for that
matter, and not only in proc_alloc_inum().
NAKed. Don't do it. request_irq() is not to be called under spinlocks,
with or without irqs disabled.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: MaJun <majun258@huawei.com>
Cc: ebiederm@xmission.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org,
dhowells@redhat.com, Waiman.Long@hp.com, dingtianhong@huawei.com,
guohanjun@huawei.com, fanjinke1@huawei.com
Subject: Re: [PATCH] Change the spin_lock/unlock_irq interface in proc_alloc_inum() function
Date: Wed, 2 Mar 2016 03:09:41 +0000 [thread overview]
Message-ID: <20160302030941.GH17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1456886879-28128-1-git-send-email-majun258@huawei.com>
On Wed, Mar 02, 2016 at 10:47:59AM +0800, MaJun wrote:
> From: Ma Jun <majun258@huawei.com>
>
> 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()
Do you even read your own patch?
> if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
^^^^^^^^^^
This.
It can block. You *can't* call that under spin_lock_irqsave(). At all.
You also can't do request_irq() under a spinlock, no matter whether you
disable irqs or not - it also blocks. So does proc_mkdir(), for that
matter, and not only in proc_alloc_inum().
NAKed. Don't do it. request_irq() is not to be called under spinlocks,
with or without irqs disabled.
next prev parent reply other threads:[~2016-03-02 3:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 2:47 [PATCH] Change the spin_lock/unlock_irq interface in proc_alloc_inum() function MaJun
2016-03-02 2:47 ` MaJun
2016-03-02 3:09 ` Al Viro [this message]
2016-03-02 3:09 ` Al Viro
2016-03-02 6:32 ` majun (F)
2016-03-02 6:32 ` majun (F)
2016-03-02 17:29 ` Al Viro
2016-03-02 17:29 ` Al Viro
2016-03-02 17:57 ` Al Viro
2016-03-02 17:57 ` Al Viro
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