linux-kernel - Re: [PATCH] PCI: pciehp

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Message-ID: <4973DEFF.9040203@jp.fujitsu.com>
Date:	Mon, 19 Jan 2009 11:01:35 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	Jiri Slaby <jirislaby@...il.com>
CC:	jbarnes@...tuousgeek.org, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Kristen Carlson Accardi <kristen.c.accardi@...el.com>
Subject: Re: [PATCH] PCI: pciehp_core, fix lock imbalance

Jiri Slaby wrote:
> set_lock_status omits mutex_unlock in fail path. Add the omitted
> unlock.
> 
> As a result a lockup caused by this can be triggered from userspace
> by writing 1 to /sys/bus/pci/slots/.../lock often enough.
> 
> Signed-off-by: Jiri Slaby <jirislaby@...il.com>
> Cc: Kristen Carlson Accardi <kristen.c.accardi@...el.com>
> Cc: Jesse Barnes <jbarnes@...tuousgeek.org>
> ---
>  drivers/pci/hotplug/pciehp_core.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index 5482d4e..c248554 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -126,8 +126,10 @@ static int set_lock_status(struct hotplug_slot *hotplug_slot, u8 status)
>  	mutex_lock(&slot->ctrl->crit_sect);
>  
>  	/* has it been >1 sec since our last toggle? */
> -	if ((get_seconds() - slot->last_emi_toggle) < 1)
> +	if ((get_seconds() - slot->last_emi_toggle) < 1) {
> +		mutex_unlock(&slot->ctrl->crit_sect);
>  		return -EINVAL;
> +	}
>  
>  	/* see what our current state is */
>  	retval = get_lock_status(hotplug_slot, &value);

Good catch!

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>

Thanks,
Kenji Kaneshige


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