linux-kernel - Re: [PATCH v4] perf, x86: Fix multi-segment problem of perf_event_intel

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] [day] [month] [year] [list]

Date:	Wed, 16 Sep 2015 10:52:05 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Taku Izumi <izumi.taku@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...hat.com, acme@...nel.org,
	hpa@...or.com, x86@...nel.org, jolsa@...hat.com
Subject: Re: [PATCH v4] perf, x86: Fix multi-segment problem of
 perf_event_intel_uncore

On Thu, Sep 17, 2015 at 01:17:12AM +0900, Taku Izumi wrote:

> +struct pci2phy_map {
> +	struct list_head list;
> +	int segment;
> +	int pbus_to_physid[256];
> +};

> +struct pci2phy_map *__find_pci2phy_map(int segment)
> +{
> +	struct pci2phy_map *map, *alloc = NULL;
> +
> +	lockdep_assert_held(&pci2phy_map_lock);
> +
> +lookup:
> +	list_for_each_entry(map, &pci2phy_map_head, list) {
> +		if (map->segment == segment)
> +			goto end;
> +	}
> +
> +	if (!alloc) {
> +		raw_spin_unlock(&pci2phy_map_lock);
> +		alloc = kmalloc(sizeof(struct pci2phy_map), GFP_KERNEL);

Do we want kzalloc() ? we unconditionally initialize the list and
segment thingies, but that array is not initialized here. Or is there a
better/safer value to initialize that array with?

Looking at uncore_pcibus_to_physid(), -1 might be a good value to use.

> +		raw_spin_lock(&pci2phy_map_lock);
> +
> +		if (!alloc)
> +			return NULL;
> +
> +		goto lookup;
> +	}
> +
> +	map = alloc;
> +	alloc = NULL;
> +	map->segment = segment;
> +	list_add_tail(&map->list, &pci2phy_map_head);
> +
> +end:
> +	kfree(alloc);
> +	return map;
> +}

Other than that I think the patch looks OK now.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/