From: Bjorn Helgaas <bhelgaas@google.com>
To: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Grant Likely <grant.likely@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jakub Sitnicki <jsitnicki@gmail.com>,
Vivek Goyal <vgoyal@redhat.com>,
Jiang Liu <jiang.liu@linux.intel.com>,
Mike Travis <travis@sgi.com>, Thierry Reding <treding@nvidia.com>,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v3 1/4] kernel/resource: Invalid memory access in __release_resource
Date: Wed, 22 Apr 2015 11:47:01 -0500 [thread overview]
Message-ID: <20150422164701.GJ20701@google.com> (raw)
In-Reply-To: <1429719261-18024-2-git-send-email-ricardo.ribalda@gmail.com>
On Wed, Apr 22, 2015 at 06:14:18PM +0200, Ricardo Ribalda Delgado wrote:
> When a resource is initialized via of_platform_populate.
> resource->parent is initialized to NULL via kzalloc.
> (of_platform_populate->of_device_alloc->of_address_to_resource)
>
> If of_platform_depopulate is called later, resource->parent is
> accessed (Offset 0x30 of address 0), causing a kernel error.
>
> This patch evaluates resouce->parent before accessing it. If it
> is not initialized, -EACCESS is returned.
>
> Also a WARN is thrown, so the developer can have a hint about what
> needs to be fixed.
>
> Fixes:
> BUG: unable to handle kernel NULL pointer deference at 0000000000000030
> IP: release_resource+0x26/0x90
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
> kernel/resource.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 90552aa..b7b270f 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -237,6 +237,9 @@ static int __release_resource(struct resource *old)
> {
> struct resource *tmp, **p;
>
> + if (WARN_ON(!old->parent))
> + return -EINVAL;
I'm not really a fan of this. The NULL pointer oops is a very good clue
all by itself, and it doesn't require any extra code here.
> p = &old->parent->child;
> for (;;) {
> tmp = *p;
> --
> 2.1.4
>
next prev parent reply other threads:[~2015-04-22 16:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-22 16:14 [PATCH v3 0/4] Fix null pointer deference when calling of_platform_depopulate Ricardo Ribalda Delgado
2015-04-22 16:14 ` [PATCH v3 1/4] kernel/resource: Invalid memory access in __release_resource Ricardo Ribalda Delgado
2015-04-22 16:47 ` Bjorn Helgaas [this message]
2015-04-23 8:06 ` Ricardo Ribalda Delgado
2015-04-22 16:14 ` [PATCH v3 2/4] base/platform: Only insert MEM and IO resources Ricardo Ribalda Delgado
2015-04-22 16:14 ` [PATCH v3 3/4] base/platform: Continue on insert_resource() error Ricardo Ribalda Delgado
2015-04-22 16:44 ` Bjorn Helgaas
2015-04-23 7:55 ` Ricardo Ribalda Delgado
2015-04-23 13:26 ` Bjorn Helgaas
2015-04-23 16:54 ` Thierry Reding
2015-04-22 16:14 ` [PATCH v3 4/4] of/platform: Use platform_device interface Ricardo Ribalda Delgado
2015-04-22 16:25 ` Rob Herring
2015-04-23 7:28 ` Ricardo Ribalda Delgado
2015-04-23 13:49 ` Ricardo Ribalda Delgado
2015-05-24 19:29 ` [PATCH v3.1 " Greg Kroah-Hartman
2015-05-26 7:26 ` Ricardo Ribalda Delgado
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