linux-kernel - RE: [PATCH v2] vfio: Use WARN_ON for low-probability allocation failure issue in vfio_pci_bus

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <DS0PR11MB6373BAF9CFEC4D67DEAAB1F7DC6C2@DS0PR11MB6373.namprd11.prod.outlook.com>
Date: Mon, 15 Jan 2024 15:41:02 +0000
From: "Wang, Wei W" <wei.w.wang@...el.com>
To: Kunwu Chan <chentao@...inos.cn>, "alex.williamson@...hat.com"
	<alex.williamson@...hat.com>
CC: "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2] vfio: Use WARN_ON for low-probability allocation
 failure issue in vfio_pci_bus_notifier

On Monday, January 15, 2024 2:35 PM, Kunwu Chan wrote:
> kasprintf() returns a pointer to dynamically allocated memory which can be
> NULL upon failure.
> 
> This is a blocking notifier callback, so errno isn't a proper return value. Use
> WARN_ON to small allocation failures.
> 
> Signed-off-by: Kunwu Chan <chentao@...inos.cn>
> ---
> v2: Use WARN_ON instead of return errno
> ---
>  drivers/vfio/pci/vfio_pci_core.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1cbc990d42e0..61aa19666050 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -2047,6 +2047,7 @@ static int vfio_pci_bus_notifier(struct notifier_block
> *nb,
>  			 pci_name(pdev));
>  		pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
>  						  vdev->vdev.ops->name);
> +		WARN_ON(!pdev->driver_override);

Saw Alex's comments on v1. Curious why not return "NOTIFY_BAD" on errors though
less likely? Similar examples could be found in kvm_pm_notifier_call, kasan_mem_notifier etc.