linux-kernel - Re: [PATCH v4 4/9] dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn

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: <CAPcyv4jeX+SMhoVh-wwuNozn5-E-4hfhH7H6RpqgsBnHq30Bmg@mail.gmail.com>
Date:	Mon, 8 Jun 2015 09:36:46 -0700
From:	Dan Williams <dan.j.williams@...el.com>
To:	"Elliott, Robert (Server Storage)" <Elliott@...com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"axboe@...nel.dk" <axboe@...nel.dk>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"arnd@...db.de" <arnd@...db.de>,
	"linux-nvdimm@...ts.01.org" <linux-nvdimm@...ts.01.org>,
	"benh@...nel.crashing.org" <benh@...nel.crashing.org>,
	"hpa@...or.com" <hpa@...or.com>,
	"david@...morbit.com" <david@...morbit.com>,
	"heiko.carstens@...ibm.com" <heiko.carstens@...ibm.com>,
	"mingo@...nel.org" <mingo@...nel.org>,
	"tj@...nel.org" <tj@...nel.org>,
	"paulus@...ba.org" <paulus@...ba.org>,
	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	"torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
	"hch@....de" <hch@....de>,
	"schwidefsky@...ibm.com" <schwidefsky@...ibm.com>
Subject: Re: [PATCH v4 4/9] dax: fix mapping lifetime handling, convert to
 __pfn_t + kmap_atomic_pfn_t()

On Mon, Jun 8, 2015 at 9:29 AM, Elliott, Robert (Server Storage)
<Elliott@...com> wrote:
>> -----Original Message-----
>> From: Linux-nvdimm [mailto:linux-nvdimm-bounces@...ts.01.org] On Behalf
>> Of Dan Williams
>> Sent: Friday, June 05, 2015 3:19 PM
>> Subject: [PATCH v4 4/9] dax: fix mapping lifetime handling, convert to
>> __pfn_t + kmap_atomic_pfn_t()
> ...
>> diff --git a/arch/powerpc/sysdev/axonram.c
>> b/arch/powerpc/sysdev/axonram.c
>> index e8657d3bc588..20725006592e 100644
>> --- a/arch/powerpc/sysdev/axonram.c
>> +++ b/arch/powerpc/sysdev/axonram.c
> ...
>> @@ -165,9 +166,13 @@ static int axon_ram_probe(struct platform_device
>> *device)
>>  {
>>       static int axon_ram_bank_id = -1;
>>       struct axon_ram_bank *bank;
>> -     struct resource resource;
>> +     struct resource *resource;
>>       int rc = 0;
>>
>> +     resource = devm_kzalloc(&device->dev, sizeof(*resource),
>> GFP_KERNEL);
>> +     if (!resource)
>> +             return -ENOMEM;
>> +
>
> Since resource is now a pointer...
>
> ...
>> @@ -184,13 +189,13 @@ static int axon_ram_probe(struct platform_device
>> *device)
>>
>>       bank->device = device;
>>
>> -     if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0)
>> {
>> +     if (of_address_to_resource(device->dev.of_node, 0, resource) != 0) {
>>               dev_err(&device->dev, "Cannot access device tree\n");
>>               rc = -EFAULT;
>>               goto failed;
>>       }
> ...
>
> ... I'd expect to see a devm_kfree call added after the failed label,
> like was  done here:

No, because unlike dccsblk the axon_ram driver actually adheres to the
device model, so it will be auto-freed on failed probe.  The dcssblk
implementation is not a proper "driver" so we don't get the
devres_release_all() until the device is unregistered.  That causes
the "resource" object to stick around longer than necessary unless we
force devm_kfree() it.
--
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/