From: Ladislav Michl <ladis@linux-mips.org>
To: Qi Hou <qi.hou@windriver.com>
Cc: tony@atomide.com, linux@armlinux.org.uk,
linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH, v2] arm: omap2: timer: fix a kmemleak caused in omap_get_timer_dt
Date: Tue, 9 Jan 2018 12:52:22 +0100 [thread overview]
Message-ID: <20180109115222.GA28346@lenoch> (raw)
In-Reply-To: <1515489861-1474-1-git-send-email-qi.hou@windriver.com>
On Tue, Jan 09, 2018 at 05:24:21PM +0800, Qi Hou wrote:
> When more than one GP timers are used as kernel system timers and the
> corresponding nodes in device-tree are marked with the same "disabled"
> property, then the "attr" field of the property will be initialized
> more than once as the property being added to sys file system via
> __of_add_property_sysfs().
>
> In __of_add_property_sysfs(), the "name" field of pp->attr.attr is set
> directly to the return value of safe_name(), without taking care of
> whether it's already a valid pointer to a memory block. If it is, its
> old value will always be overwritten by the new one and the memory block
> allocated before will a "ghost", then a kmemleak happened.
As timers does not seem to be deallocated, this does not matter in practice.
Fix eats a bit more from heap.
> That the same "disabled" property being added to different nodes of device
> tree would cause that kind of kmemleak overhead, at leat once.
>
> To fix it, allocate the property dynamically, and delete static one.
>
> Signed-off-by: Qi Hou <qi.hou@windriver.com>
> ---
> arch/arm/mach-omap2/timer.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index ece09c9..206ae8d 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -156,12 +156,6 @@ static struct clock_event_device clockevent_gpt = {
> .tick_resume = omap2_gp_timer_shutdown,
> };
>
> -static struct property device_disabled = {
> - .name = "status",
> - .length = sizeof("disabled"),
> - .value = "disabled",
> -};
> -
> static const struct of_device_id omap_timer_match[] __initconst = {
> { .compatible = "ti,omap2420-timer", },
> { .compatible = "ti,omap3430-timer", },
> @@ -203,8 +197,17 @@ static struct device_node * __init omap_get_timer_dt(const struct of_device_id *
> of_get_property(np, "ti,timer-secure", NULL)))
> continue;
>
> - if (!of_device_is_compatible(np, "ti,omap-counter32k"))
> - of_add_property(np, &device_disabled);
> + if (!of_device_is_compatible(np, "ti,omap-counter32k")) {
> + struct property *prop;
> +
> + prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> + if (!prop)
> + return NULL;
> + prop->name = "status";
> + prop->length = sizeof("disabled");
> + prop->value = "disabled";
How about (see drivers/of/unittest.c)?
prop->value = "disabled";
prop->length = strlen(prop->value);
> + of_add_property(np, prop);
> + }
> return np;
> }
>
> --
> 2.7.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2018-01-09 12:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-09 9:24 [PATCH, v2] arm: omap2: timer: fix a kmemleak caused in omap_get_timer_dt Qi Hou
2018-01-09 11:52 ` Ladislav Michl [this message]
2018-01-10 9:08 ` qhou
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180109115222.GA28346@lenoch \
--to=ladis@linux-mips.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=qi.hou@windriver.com \
--cc=tony@atomide.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).